UNIVERSITY OF

ILLINOIS LIBRARY

AT URBANA-CHAMPAIGN

BIOUOGY

2001

FB

Botany

RIES. NO 3

William Burger, Editor

Family #113 Euphorbiaceae

William Burger

Michael Huft

October 31, 1995

Publication 1469

3ARYO

996

IN

PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY

FIELDIANA

Botany

NEW SERIES, NO. 36

FLORA COSTARICENSIS

William Burger, Editor

Family #113 Euphorbiaceae

William Burger

Curator, Department of Botany

Field Museum of Natural History

Roosevelt Road at Lake Shore Drive

Chicago, Illinois 60605-2496

Michael Huft

Research Associate

Department of Botany

Field Museum of Natural History

Roosevelt Road at Lake Shore Drive

Chicago, Illinois 60605-2496

Accepted May 11, 1995

Published October 31, 1995

Publication 1469

PUBLISHED BY FIELD MUSEUM OF NATURAL HISTORY

© 1995 Field Museum of Natural History

ISSN 00 15-0746

PRINTED IN THE UNITED STATES OF AMERICA

Table of Contents

INTRODUCTION v

ACKNOWLEDGMENTS v

EUPHORBIACEAE 1

Key 1 : Key to the Genera of Euphorbi-

aceae in Costa Rica 2

Key 2: Artificial Key to Genera and Un-

usual Species 7

Illustrations of Euphorbiaceae 14

Descriptions of Genera and Species 46

Acalypha 46

Croton 84

Euphorbia 113

Phyllanthus 140

LITERATURE CITED 163

LIST OF ACCEPTED SPECIES 1 64

INDEX . 166

List of Illustrations

1 . Shrubs or treelets with deeply lobed

leaves: species of Manihot and Ricinus 14

2. Vines and subshrubs with lobed leaves:

species of Croton, Cnidoscolus, and

Tragia 15

3. Trees and shrubs with deeply to slight-

ly lobed leaves with palmate venation:

species of Jatropha 16

4. Slender-stemmed vines with lobed or

compound leaves: species of Dale-

champia 17

5. Slender-stemmed vines: species of Dal-

echampia, Plukenetia, and Tragia 18

6. Plants with very small leaves: species

of Chamaesyce and Euphorbia 19

7. Plants with small opposite leaves: spe-

cies of Chamaesyce 20

8. Plants with small alternate leaves: spe-

cies of Phyllanthus 21

9. Plants with small alternate leaves: spe-

cies of Phyllanthus 22

10. Herbaceous or weedy plants: species of

Caperonia, Croton, and Dysopsis 23

1 1 . Herbaceous or weedy plants: species of

Acalypha, Argythamnia, and Sebasti-

ania . . 24

12. Trees and shrubs with serrate elliptic

leaves: species ofAcidoton, Alchornea,

Bernardia, Cleidion, Croton, and Gym-

nanthes 25

13. Plants with larger oblanceolate serrate

leaves: species of Adenophaedra, Dale-

champia, and Pausandra 26

1 4. Shrubs or herbs with serrate leaves and

laciniate styles: species of Acalypha .... 27

15. Shrubs with serrate leaves and lacini-

ate styles: species of Acalypha 28

16. Plants with slightly serrate leaves and

stellate hairs: species of Croton 29

17. Trees and shrubs with flat peltate

hairs: species of Croton 30

18. Trees and shrubs with larger ovate

leaves, stellate hairs, and glands at

apex of petiole: species of Croton 31

19. Trees and shrubs with larger ovate or

oblong leaves and stellate or peltate

hairs: species of Croton 32

20. Trees with larger leaves: species of

Aparisthmium, Conceveiba, Sagotia,

and Tetrorchidium 33

2 1 . Trees with glands on petioles or a

thickened petiole apex: species of Gar-

cia and Tetrorchidium 34

22. Trees with glands on petioles: species

of Sapium 35

23. Trees with glands on petioles (Sapium

spp.) or shrubs with glands along lami-

na margins (Stillingia sp.) 36

24. Trees with slightly serrate leaves and

subpalmate or palmate venation: spe-

cies of Alchornea and Alchorneopsis .... 37

25. Trees and shrubs with entire or subser-

rate leaves: species of Actinostemon,

Margaritaria, Phyllanthus, and Sebas-

tiania 38

26. Trees and shrubs with entire elliptic

leaves: species of Gymnanthes, Mabea,

and Pera 39

27. Trees and shrubs with entire elliptic

leaves: species of Amanoa and Dry-

petes 40

28. Trees with spicate inflorescences or in-

florescence branches: species of Hy-

eronima and Richeria 41

29. Herbs or weak-stemmed shrubs with

entire leaves and white sap: species of

Euphorbia 42

30. Shrubs and trees with small entire

leaves and white sap: species of Eu-

phorbia 43

in

3 1 . Climbers and unusual plants: species 32. Trees and shrubs with distinctive

ofAdelia, Mabea, Omphalea, and Plu- leaves: species of Astrocasia, Cod-

kenetia 44 iaeum, Hippomane, and Hura . . 45

IV

Introduction

This is the ninth issue in the Flora Costaricensis

series. The first dealt with the Piperaceae, family

number 41 (Fieldiana, Bot. 35, 1971). The second

included families numbered 42 through 53, Chlo-

ranthaceae through Urticaceae (Fieldiana, Bot. 40,

1 977). The third issue covered the Gramineae (Po-

aceae) and was authored by Richard Pohl (Field-

iana, Bot., n.s. No. 4, 1980). The fourth issue in-

cluded families numbered 54 through 70, Podo-

stemaceae through Caryophyllaceae (Fieldiana,

Bot., n.s. No. 13, 1983). The fifth issue covered

families 200 and 201, the Acanthaceae, authored

by L. H. Durkee, and Plantaginaceae (Fieldiana,

Bot., n.s. No. 18, 1986). The sixth issue included

families 80 and 8 1 , Lauraceae and Hernandiaceae

(Fieldiana, Bot., n.s. No. 23, 1990). The seventh

issue included families numbered 97 through 103,

Krameriaceae through Zygophyllaceae (Fieldiana,

Bot., n.s. No. 28, 1991). The eighth issue included

family 202, the Rubiaceae (Fieldiana, Bot., n.s.

No. 33, 1993).

In the figures, leaves and leafy stems are drawn

to the same scale throughout. Enlarged flowers and

fruits are drawn to the same scale on an individual

plate unless otherwise noted. The closed scales

represent centimeters, and the open scales repre-

sent millimeters. The figures are somewhat dia-

grammatic and represent the senior author's con-

cept of a common or characteristic morphology.

Acknowledgments

We wish to thank the staff of the Museo Na-

tional de Costa Rica for their assistance in col-

lecting programs over many years. The National

Science Foundation and the National Geographic

Society helped support many of these collecting

activities. The Missouri Botanical Garden and the

Institute Nacional de Biodiversidad have been es-

pecially active in enriching our knowledge of Costa

Rica's flora in recent years. Dr. Michael Huft, on

the staff of the Missouri Botanical Garden and

stationed at the Field Museum, worked with Neo-

tropical euphorbs for more than a decade. His

determinations and taxonomic concepts served as

the foundation for the present treatment. The col-

lections of the Field Museum, the Missouri Bo-

tanical Garden, Duke University, and the U.S.

National Herbarium were consulted in preparing

this treatment, and we thank those institutions for

the use of their materials.

We have benefited from the annotations and

publications of many taxonomists; they are ac-

knowledged in the generic treatments and in the

keys to genera. Three anonymous reviewers were

very helpful, providing many detailed corrections

and useful suggestions.

FLORA COSTARICENSIS

Family #113 Euphorbiaceae

EUPHORBIACEAE

By William Burger and Michael Huft

Trees and shrubs or less often herbs, vines, and lianas,

sometimes with thick green cactus-like stems and re-

duced leaves in African and ornamental species, monoe-

cious (bisexual) or dioecious (unisexual), sap often with

colored or whitish latex (sap strongly caustic in Hippom-

ane and some Euphorbia spp.), glabrous or pubescent,

trichomes simple, stellate, scurfy, or rounded and peltate

with flat apex (cf. Crotori), stinging hairs present in some

genera (cf. Cnidoscolus and Tragia); stipules usually 2

and lateral at the petiole base (rarely 1 or 0), often falling

early (caducous). Leaves usually alternate (opposite in

Chamaesyce, Euphorbia spp., et al.), simple (rarely tri-

foliolate or palmately compound as in Dalechampia spp.

and Heved), petioles usually present, often with promi-

nent glands distally or at the base of the blade (Croton,

Sapium, et al.); leaf blades entire to serrate, sometimes

palmately lobed (rarely irregularly pinnately lobed as in

Codiaeum, Euphorbia spp.), glabrous to pubescent, ve-

nation pinnate or palmate, often with glands along the

edge or imbedded in blade, domatia rarely present. In-

florescences terminal, axillary or extra-axillary, usually

solitary or few/node, unisexual or bisexual, the bisexual

usually with the 2 flowers proximal and the more nu-

merous $ flowers distal, very variable in form (spikes,

racemes, cymes, thyrses, paniculate or of solitary or fas-

ciculate flowers) but most often with flowers in distal

cymes, inflorescences forming pseudo-flowers (pseudan-

thia) in Chamaesyce, Euphorbia, and Pedilanthus (called

cyathia) and with less tightly organized pseudanthia in

Dalechampia and Pera; flowers always unisexual but the

pseudanthia usually bisexual, sessile or pedicellate, usu-

ally subtended by bracts, bracts sometimes with 2 lateral

glands. Male flowers radially symmetrical, perianth

whorls 1 or 2 (rarely 0), calyx with 3-6 sepals or calyx

lobes, valvate or imbricate in bud, glabrous or puberu-

lent, petals present or absent, a disk usually present (an-

nular, lobed, flat or glandular); stamens (1-2) 3-many,

usually as many or twice as many as the perianth parts,

filaments free or united into a column (a parasol-like

androecium in Astrocasia, mushroom-like in Omphalea,

strobilus-like protuberances in Hura, distally branched

and with many anthers in Ricinus), anthers 2- or

4-thecous, usually dehiscing longitudinally, pollen grains

of many differing types and often important in deter-

mining generic relationships; a pistillode present or ab-

sent. Female flowers radially symmetrical, perianth of 1

or 2 whorls (reduced or absent in a number of genera),

calyx with 3-8 sepals or calyx lobes, imbricate, valvate

or united in bud, corolla usually of separate petals or

absent, disk present or absent, annular to lobed or cu-

pulate, staminodes usually absent; ovary superior, loc-

ules usually 3 (1-20), styles usually the same number as

the locules, free or united into a short or long column,

style branches simple or divided to laciniate distally,

ovules 1 or 2 in each locule, usually pendulous. Fruits

usually capsules (schizocarps), rarely berries or drupes,

the capsules characteristically separating septicidally into

2-valved cocci (mericarps) that open loculicidally and

explosively on the inner face, a central columella often

remaining after dehiscence; seeds often with an adaxial

line or scar (ventral raphe), a thickened or fleshy caruncle

often present at the micropylar attachment site, surfaces

smooth to rugose, endosperm usually copious and oily,

sometimes containing poisonous compounds.

The Euphorbiaceae are a large and important

family with an estimated 7,700 species (Mabber-

ley, 1987) in 317 genera (Webster, 1994b). Except

for the polar regions, the family is worldwide in

range but with the great majority of species in

tropical and subtropical regions. The family in-

cludes important agricultural taxa (Hevea, Mani-

hot, Ricinus), medicinal plants, timber trees, and

garden ornamentals (Acalypha, Codiaeum, Eu-

phorbia, Ricinus) (see Mabberley, 1987, and other

references under Literature Cited). The taxonomy

of the Euphorbiaceae was recently the subject of

a symposium (in Ann. Missouri Bot. Card. 81,

parts 1 and 2, 1994). The relationships of the Eu-

phorbiaceae have been the subject of many dif-

ferent opinions (Webster, 1987). For a recent over-

view of the family, see Webster (1994a, b).

The Euphorbiaceae are often difficult to iden-

tify, both as to family and as to genera. The small

unisexual flowers of great morphological diversity

(often on unisexual trees and shrubs) account for

some of this difficulty. Flowering material may be

difficult to recognize as euphorbiaceous when only

$ flowers are present. The usually three-parted

ovaries, capsular fruits often breaking open explo-

sively, and the characteristic seeds allow many

fruiting collections to be quickly determined to

family. The presence of milky or colored latex/sap

or stellate-lepidote-peltate hairs can aid in deter-

mination of some genera. Many species of Eu-

phorbiaceae have flat or elevated glands at or near

the junction of the petiole and leaf blade or small

glands along the edge of the blade. Specimens of

FIELDIANA: BOTANY, N.S., NO. 36, OCTOBER 31, 1995, PP. 1-169

Euphorbiaceae may be mistaken for species of Fla-

courtiaceae (but these usually have bisexual flow-

ers), Moraceae (especially Sorocea and Trophis),

and Urticaceae. Ornamental leafless succulent spe-

cies with spines are often confused with Cactaceae,

but the flowers and fruits easily distinguish the

two families. Also, succulent euphorbs never have

the tiny hooked hairs (glochids) found in many

cacti, whereas cacti rarely have the milky sap found

in many succulent euphorbs.

To aid in identification, we provide two separate

keys to genera. The first is a technical key based

on the characteristics that help define the genera,

and this key may be useful over a broader region.

This key is based on the key developed by Webster

(in Webster & Huft, 1988) and to a lesser extent

on one by Gillespie (1993). The second key is an

artificial key that is intended to be easy to use but

that may not be helpful with atypical material or

material new to southern Central America. Hope-

fully, the illustrations will serve as an additional

aid to identification, especially when critical floral

features are not available. The illustrations are ar-

ranged in a series of artificial "look-alike" group-

ings.

Key 1: Key to the Genera of Euphorbiaceae in Costa Rica

(Based on the Key of Webster in Webster & Huft, 1988.)

.,

la.

Ovules 2 in each locule of the ovary (seeds 1/locule in Drypetes and in Astrocasid); seeds 1-2 in

each locule of the fruit, often 6/fruit (also 1-4/fruit), without caruncle; whitish latex absent; leaf

blades never lobed, usually entire to obscurely serrate, usually lacking imbedded laminar glands,

usually pinnately veined; trichomes simple or peltate [subfamily Phyllanthoideae and Croizatia of

the Oldfieldioideae] 2

Ib. Ovule 1 in each locule of the ovary; seeds usually 3/fruit, seeds with or without an apical caruncle;

whitish or colored latex present or absent; leaf blades often serrate or lobed (also entire), often

with glands on blade or petiole, venation pinnate or palmate; trichomes various 10

2a. Petals present in the flowers 3

2b. Petals absent in the flowers 5

3a. Petals equaling or longer than the sepals; filaments connate and forming a parasol-like

androecium; 9 disk forming a thin corolla-like cup; seeds with copious endosperm [rare

in southern Central America] Astrocasia

3b. Petals much shorter than the sepals; filaments free or connate, not forming a parasol-

like androecium; 9 flower without a thin cupulate disk; seeds with little or copious

endosperm 4

4a. Plants monoecious (bisexual); stipules united above the petiole (intrapetiolar); petals

glabrous; styles bifid and expanded; columella narrowed toward apex, without apical

wings Amanoa

4b. Plants dioecious (unisexual); stipules not united above the petiole; petals puberulent;

style twice bifid (pistil with 1 2 style branches); columella expanded distally forming 3

papery wings [eastern Panama and South America, not included in text] . . Croizatia

5a. $ inflorescences spikes or racemes; 3 flowers with prominent pistillode; plants dioecious

(unisexual) 6

5b. $ inflorescences of axillary flower clusters or on deciduous branchlets if racemose; $ flowers

lacking a prominent pistillode; plants monoecious (bisexual) or dioecious 7

6a. Trichomes simple; calyx deeply lobed (almost of separate sepals); <5 inflorescences

spicate with sessile flower clusters; anther thecae not pendulous; ovary 2-3-locular;

fruits dry capsules Richeria

6b. Trichomes mostly peltate; calyx with short lobes; $ inflorescences with alternate branch-

es; anther thecae pendulous; ovary 2-locular; fruits fleshy and drupaceous

Hyeronima

7a. $ flowers with a central intrastaminal disk; ovary with 1 or 2 locules, stigmas sessile and

expanded; fruits drupaceous; ovules 1/locule; dioecious (unisexual) trees Drypetes

FIELDIANA: BOTANY

7b. $ flowers without a central disk or the disk outside the stamens if present; ovary with 3-6

locules and styles, styles present and bifid, stigmas slender or expanded; fruits mostly capsules;

ovules 2/locule; plants monoecious (bisexual) or dioecious 8

8a. Ovary with 4 or 5 locules (rarely 3, 6), styles 4 or 5 (3, 6); fruits irregularly dehiscent; seeds

with fleshy outer coat and hard bony inner coat; $ flower with annular (ring-like) disk and

4 free stamens; distal branchlets persisting, not resembling pinnate leaves; dioecious trees

Margaritaria

8b. Ovary with 3 (rarely 2) locules, styles 3 (2); fruit usually breaking into valves; seeds without

both a fleshy and bony layer; 3 flowers with 2 or 3 stamens, or without a disk when 4 stamens

are present; distal branchlets often deciduous and resembling pinnate leaves; monoecious or

dioecious 9

9a. Common wild trees, shrubs, and herbs with green leaves; seeds dry, ventral faces not in-

vaginated; floral disk usually present Phyllanthus

9b. Ornamental garden shrubs with variegated leaves; seeds with fleshy exotesta, ventral face

invaginated; floral disk absent Breynia

lOa. (from Ib) Floral bracts without glands at the base (present in Tetrorchidium); sepals imbricate to

valvate, usually covering the anthers completely in bud, rarely petaloid; petals present or absent;

disk often present; trichomes various; leaves simple to palmately lobed or compound 11

1 Ob. Floral bracts with 2 glands at the base (but sometimes difficult to see, absent in Hura and Senfelderd);

sepals imbricate or not well developed; anthers mostly exposed in bud; petals absent and the sepals

not petaloid, but glands of involucral cup may have petal-like lobes; disk absent or minute;

trichomes simple or absent (dendritic in Mabed); leaves without lobes [subfamily Euphorbioideae]

37

11 a. Petals absent, or if petals present the leaf blades with pinnate venation; petioles lacking

stalked glands (but glands imbedded in leaf blades often present); seeds lacking caruncles

(caruncles present in Pera and Ricinus); trichomes simple or attached at the center (peltate

in Pera); flowers in axillary clusters, racemes, or spikes (these sometimes aggregated into

panicles); latex usually absent, rarely white (subfamily Acalyphoideae) 12

lib. Petals present, at least in the $ flowers, or else calyx petaloid (except in Tetrorchidium, with

raised foliar glands, and in Croton punctatus); leaves often palmately veined or lobed; petioles

or bases of the leaf blades often with stalked or prominent glands; seeds with caruncles or

fleshy (except in Garcia); trichomes simple, attached in the center, stellate or peltate; inflo-

rescences various; latex clear, colored or whitish (subfamily Crotonoideae) 29

12a. Petals present in both $ and 2 flowers [flowers in racemes; 6 flowers with 10 stamens;

seeds usually foveolate] 13

1 2b. Petals absent (3 petals in 2 Caryodendrori) 14

1 3a. Leaves serrulate, 2° veins straight, more than 6/side and clearly parallel; trichomes

simple or gland-tipped; 6 flowers with a pistillode Caperonia

1 3b. Leaves entire, 2° veins arcuate-ascending, fewer than 5/side and not clearly par-

allel; trichomes often attached at the center; 3 flowers lacking a pistillode

Argythamnia

1 4a. Flowers sessile within a globose stipitate flower-like inflorescence, at first enclosed by

the petal-like involucre; inflorescences resembling globose flower buds borne on leafless

nodes below the leaves; seeds smooth and shiny black with caruncle [dioecious trees

with peltate or stellate trichomes] Pera

14b. Flowers not sessile nor enclosed in a stipitate involucre; inflorescences not resembling

pedicellate flower buds in early stages; seeds neither black nor shiny 15

1 5a. Flowers in a complex flower-like arrangement (pseudanthium) with 2 usually conspic-

uous palmately veined bracts often held in a vertical plane [ovary and fruit usually

armed with stinging hairs; plants mostly vines or lianas with palmately veined or lobed

leaves, or with palmately compound leaves] Dalechampia

1 5b. Flowers not in a complex pseudanthium with 2 large palmately veined bracts held in

a vertical plane 16

1 6a. Stamens resembling little trees, with many distal branches bearing 80-many anthers;

BURGER & HUFT: FLORA COSTARICENSIS

leaf blades peltate and palmately lobed; inflorescences with 2 flowers distal and 6 flowers

proximal; seeds with caruncles [introduced plants] Ricinus

1 6b. Stamens not branched and tree-like with so many anthers; leaf blades never peltate or

palmately lobed; inflorescences usually with 9 flowers proximal; seeds with minute

caruncle or caruncle absent 17

1 7a. <5 flowers with 4 sepals imbricate in 2 whorls, stamens 2, completely united and mush-

room-shaped with connective enlarged and fleshy; latex reddish or purplish; fruits 8-

1 2 cm diam. [globose; plants usually lianas] Omphalea

1 7b. <5 flowers with 3-5 valvate sepals, stamens 3-many (if 2 then the connective not en-

larged); latex not reddish or purplish; fruits less than 7 cm diam 18

1 8a. Stinging hairs present [styles undivided and connate basally; disk absent; seeds smooth,

caruncle absent] 19

1 8b. Stinging hairs absent 20

1 9a. Anthers lacking a minute tuft of apical hairs; bisexual vines; leaf blades usually

cordate at base, usually with many stinging hairs Tragia

1 9b. Anthers with a minute apical tuft of stinging hairs (often difficult to see); unisexual

shrubs and trees; leaf blades cuneate at base, glabrescent Acidoton

20a. Styles basally connate into a long column; inflorescences bisexual and axillary; ovary

4-locular, strongly keeled; lianas [leaf blades with 2 circular glands at base]

Plukenetia

20b. Styles free or basally connate; inflorescences unisexual, various; ovary 2-3-locular, not

strongly keeled; trees, shrubs, or herbs 21

2 la. Styles usually divided into many slender laciniate branches; anthers minute (ca. 0.1

mm wide) with narrow pendulous- vermiform thecae (but difficult to see); 2 bracts much

larger than the <5 or if not the ovary verrucose [<3 inflorescences usually slender congested

spikes] Acalypha

2 1 b. Styles various, but only divided into slender laciniate branches in Adelia; anthers usually

more than 0.2 mm wide and the thecae not narrow and pendulous- vermiform; 2 bracts

not conspicuously larger or differently shaped than the 6 bracts 22

22a. Ovary with 2 locules and 2 elongate free entire styles [stamens usually 8, pistillode

absent; seeds tuberculate, lacking a caruncle, dry; trichomes often minutely stellate]

Alchornea

22b. Ovary with 3 locules and with 3 bifid styles (or the seeds fleshy if styles are simple)

23

23a. Stamens fewer than 10; plants unisexual (dioecious) 24

23b. Stamens more than 10; plants unisexual or bisexual (monoecious) 27

24a. Herbs with creeping stems; stipules thin and persisting; capsule thin-walled . . .

Dysopsis

24b. Trees and shrubs with erect stems; stipules absent or caducous; capsules thick-

walled 25

25a. Leaves usually tripliveined; stipules absent; seed coat fleshy; a pubescent pistillode

present in <5 flowers [inflorescences axillary; 2 flowers subsessile] Alchorneopsis

25b. Leaves pinna tely veined; stipules present; seed coat not fleshy; pistillode absent

in 2 flowers 26

26a. Leaves without glands; stamens 3 , disk absent in <3 flowers; styles broadly expanded

and stigma-like; seeds < 1 cm long Adenophaedra

26b. Leaf blades with flat laminar glands at the adaxial base; stamens 4-7, disk large

in $ flowers; styles short; seeds > 1 cm long Caryodendron

27a. Stamens more than 50 in $ flowers, anther connective enlarged; stipules thickened [disk

absent in 2 flowers] Cleidion

27b. Stamens less than 30 in each 6 flower, anther connective not enlarged; stipules thin

28

28a. Styles much divided and laciniate distally, 2 flowers with long (> 18 mm) pedicels;

fruits long-pendulous; leaf blades without glands Adelia

FIELDIANA: BOTANY

28b. Styles once or twice bifid (6 or 1 2 style branches), not laciniate, 2 flowers sessile or on

pedicels to 6 mm long; fruits not pendulous; leaf blades with conspicuous glands near

the base Bernardia

29a. (from 1 1 b) Rowers without petals; stamens 3/flower, anthers peltate and appearing 4-thecous;

seeds fleshy, lacking a caruncle [dioecious/unisexual trees and shrubs; leaves with stalked

petiolar glands and trichomes attached at the center] Tetrorchidium

29b. Flowers with petals present, or if petals absent then the calyx petaloid or trichomes peltate;

stamens 8 or more per flower, anthers not appearing 4-thecous; seeds not fleshy, with a

caruncle (except Garcia) 30

30a. Flowers without petals, but the calyx petal-like [leaves palmately lobed; trichomes simple;

sap white; plants monoecious/bisexual; inflorescences terminal and dichasial or paniculate;

stamens 8-10] 31

30b. Flowers with petals, or if petals absent then the trichomes peltate; sap not whitish .... 32

3 la. Stinging hairs absent; calyx yellow to greenish or purple and often resembling a rotate

corolla; <5 flowers with free filaments and central interstaminal disk Manihot

31b. Stinging hairs present (sometimes very few); calyx whitish and not resembling a rotate

corolla; $ flowers with connate filaments and extrastaminal disk Cnidosculus

32a. Anthers inflexed in bud; some peltate or stellate trichomes usually present [<5 flowers with

8-many stamens, filaments free; inflorescences spicate or racemose (never branched); plants

usually monoecious/bisexual in Central America; seeds with caruncles] Croton

32b. Anthers usually erect in bud; trichomes not stellate or peltate 33

33a. Calyx opening into valvate segments; $ flowers with 6-13 petals, stamens 30-100 or more;

seeds without caruncles [trichomes simple; bisexual trees or shrubs] Garcia

33b. Calyx of initially separate imbricate sepals; <3 flowers with usually 5 petals, stamens 12 or

fewer; seeds with caruncles 34

34a. Leaves palmately veined or lobed; stamens mostly 8-12, filaments partly united; inflores-

cences terminal and dichasial, usually bisexual; trichomes simple or with gland-tipped seg-

ments Jatropha

34b. Leaves pinnately veined; stamens 3—40, filaments free; inflorescences terminal or axillary,

usually unisexual (unisexual or bisexual in Sagotia), spicate to racemose or paniculate; tri-

chomes never with gland-tipped segments 35

35a. Stamens 3-7; 2 flower with petals connate into a tube longer than the calyx; unisexual trees

[inflorescences axillary and spiciform; trichomes simple and attached at the center but often

difficult to see] Pausandra

35b. Stamens 15—40; 2 flower lacking petals or the petals shorter than the calyx; bisexual shrubs

and trees 36

36a. $ flowers without a disk; styles deeply bifid; inflorescences usually terminal, 1-12 cm long;

leaves never lobed or with bright variegated colors; native trees Sagotia

36b. $ flowers with a lobed disk; styles simple and unlobed inflorescences usually axillary, 10-20

cm long; leaves often with lateral lobes and brilliant variegated colors; introduced garden

shrubs Codiaeum

37a. (from lOb) Flowers not pseudanthial (as in 37b), without a well-developed involucral cup; flowers

in spicate, racemose, or paniculate inflorescences; styles simple; stamens in whorls or united, not

in radiating groups of 5 within a calyx cup or calyx tube; shrubs or trees, rarely herbs 38

37b. Flowers pseudanthial, actually flower-like inflorescences (called cyathia) in which the involucral

bracts are united to form a calyx-like cup, usually with 1-5 glands along the edge of the involucral

cup and these often with petal-like structures, central pistil actually a naked 9 flower on an articulated

stipe (pedicel), styles bifid or simple; stamens usually in 5 lateral groups within the cupulate or

shoe-shaped cyathium; cyathia often in cymose or dichotomous inflorescences; caruncle small or

absent; herbs, shrubs, or small trees; sap usually whitish (often caustic) 47

38a. Inflorescences thyrsoid or paniculate (resembling racemes in Mabea); $ flowers with anthers

subsessile on an elevated receptacle 39

38b. Inflorescences spicate or racemose; $ flowers with anthers borne on well-developed filaments

. 40

BURGER & HUFT: FLORA COSTARICENSIS

39a. Trichomes branched (dendritic); 2 flower with long stylar column; <3 flowers 2 or more/

node, long-pedicellate, stamens 10 or more in our species [inflorescences long and

racemose] Mabea

39b. Trichomes absent, plants glabrous; 2 flower with styles nearly free to the base; $ flowers

I/node, subsessile, stamens 5 [eastern Panama and South America; not included in

text] Senfeldera

40a. Stylar column at least 25 mm long, terminated by a fleshy disk 2-3 cm wide and resembling

a parasol; <5 flowers breaking their perianth irregularly in early anthesis, with anthers borne

in whorls on cone-like columns from the axis of the inflorescence; ovary and fruit with more

than 10 locules [capsule 5-9 cm diam.J Hura

40b. Stylar column < 25 mm long, styles diverging distally and not forming a flat disk; $ flowers

not rupturing the perianth and not borne on conical projections of the inflorescence axis;

ovary and fruit with fewer than 1 0 locules 41

4 la. Ovary 6-9-locular; fruits drupaceous and not splitting open [seeds lacking a caruncule; 2

flowers with 3-parted calyx; petiole with single gland; latex extremely caustic; seaside trees]

Hippomane

41b. Ovary 2-3-locular; capsules often splitting open explosively 42

42a. Seeds lacking a caruncle, seed coat fleshy; petioles usually with a pair of cylindrical glands;

2 sepals united at the base [6 flowers with 2 stamens] Sapium

42b. Seeds with a caruncle, seed coat dry; petioles without prominent glands; 2 flowers with separate

sepals 43

43a. Dehisced fruits with persistent woody 3-pronged stylobase (gynobase), columella present or

absent; stems usually with much white sap; leaf blades with paired glands near the base [seeds

with small caruncle in Central American species, rare in our area] Stillingia

43b. Dehisced fruits without a persisting woody 3-pronged stylobase, columella usually present;

stems with little or no white sap; leaf blades without stalked glands 44

44a. $ part of the inflorescence contracted to less than 1 cm long and ovoid; stamens 2 with

filaments united, styles distinctly connate; seeds with large cap-like caruncle, seed surface

foveolate [central Panama to South America and not included in text] Maprounea

44b. <3 part of the inflorescence elongated and spicate, not contracted and subglobose; stamens

usually 3-5, filaments free or partly connate; styles free or partly united in Actinostemon;

seeds with small caruncle, seed coat smooth 45

45a. Spikes terminal or opposite the leaves; <3 calyx 3-lobed, stamens 3; ovary with 3 or 6 distal

lobes or projections; fruiting pedicels < 5 mm long Sebastiania

45b. Spikes or racemes axillary or pseudoaxillary; 6 calyx minute and 1 -parted or absent; stamens

2-6 (in Costa Rica); ovary smooth; fruiting pedicels > 1 0 mm long 46

46a. Stipules and bud-scales < 1 mm long, not forming cap-like structures over shoot-apices and

early inflorescences, often persisting; inflorescences minutely puberulent or glabrous

Gymnanthes

46b. Stipules and bud-scales ca. 3 mm long, often forming a cap over shoot-apices and early

inflorescence-buds, caducous; inflorescences essentially glabrous Actinostemon

47a. (from 37b) Cyathia (flower-like pseudanthia) bilaterally symmetrical with involucre somewhat

shoe-shaped, often with reddish coloring; involucral glands borne within the nectar spur and not

visible from the exterior; styles connate into a long column; distal stems often green

Pedilanthus

47b. Cyathia radially symmetrical, involucre usually urceolate or campanulate and round in cross-

section, usually greenish, yellow or white; involucral glands usually visible at the edge of the

involucral cup; styles not forming a long column; distal stems green or woody and brown ... 48

48a. Involucre without 4-5 distinct glands alternating with lobes of the cyathium, involucre usually

saucer-shaped, red; few-branched succulent ornamental shrubs Synadenium

48b. Involucre usually with 4-5 (1-3) distinct glands alternating with the lobes on the rim of the

cyathium, involucre usually deeply cupulate or urceolate; trees, shrubs, and herbs, succulent or

not, cultivated and wild 49

49a. Leaves alternate, opposite or whorled, if opposite then blades not asymmetric at the base; stipules

FIELDIANA: BOTANY

absent or gland-like and small; veins of the leaf blades lacking a sheath of chlorenchyma; main

axis of the plant not aborting soon after germination; trees, shrubs, or herbs Euphorbia

49b. Leaves always opposite, blades usually small and strongly asymmetric at the base; stipules present

and often lobed; veins of the leaf blades with a sheath of chlorenchyma (in dried leaves the veins

often look translucent in transmitted light, in contrast to the darker areas between the veins); main

axis of the young plant aborting just above the cotyledons; herbs and small shrubs Chamaesyce

Key 2: Artificial Key to Genera and Unusual Species

la. Leaves compound with usually 3 leaflets, or the leaves simple and with prominent lobes > 20%

the length or width of the leaf blade 2

Ib. Leaves simple and without prominent lobes, the blades entire to deeply serrate, dentate or crenate,

teeth or lobes < 1 5% the width of the blades (note: simple leaves usually have buds or flowers in

the axils of their petioles but leaflets do not) 16

2a. Leaves 3-foliolate, petioles with 3 petiolate leaflets at the apex in at least some of the leaves

on the plant 3

2b. Leaves simple, petioles with a single leaf blade (the leaf blade may be deeply divided but

the divisions do not have slender petiolules at their base) 4

3a. Slender-stemmed vines; leaves sometimes simple and compound on the same stem;

native Dalechampia spp.

3b. Trees; leaves always 3-foliolate; introduced economically useful plants

Hevea brasiliensis

4a. Venation pinnate, lobes and sinuses along the lateral margins of the leaves 5

4b. Venation palmate, lobes and sinuses distal and lateral on the leaf margin 6

5a. Weedy herbs to 1 m tall Euphorbia heterophylla

5b. Garden shrubs to 5 m tall Codiaeum variegatum

6a. Leaf blades peltate, petiole attached near the center or near the edge of the blade 7

6b. Leaves with the petioles attached at the edge of the blade 8

7a. Margin of the leaf serrate; petiole attached near the center of the blade

Ricinus communis

7b. Margin of the leaf entire; petiole attached near the edge of the blade . . . Jatropha spp.

8a. Plants slender vines with clambering branches, stems becoming > 1 m long, leaves > 4 cm

long 9

8b. Plants erect herbs, trees, and shrubs, or if prostrate or procumbent and clambering the stems

< 1 m long with leaves usually < 3 cm long 11

9a. Plants without stinging hairs; inflorescences racemose with prominent pedicels (to 1 5

mm long); flowers 6-18 mm long with prominent 5-lobed or 5-parted perianth

Manihot brachyloba

9b. Plants often with stinging hairs (at least near the flowers); inflorescences not clearly

racemose; flowers lacking prominent calyx 6-18 mm long, often subtended by 2 large

perianth-like bracts 10

lOa. Inflorescences with 1 or 2 slender axes from a peduncle 1-10 cm long, floral bracts 3-

5 mm long, many along the axes Tragia bailloniana

lOb. Inflorescences flower-like with 2 large (1-6 cm) floral bracts usually held in a vertical

plane (subtending the flowers) Dalechampia spp.

11 a. Stinging hairs usually present (around the flowers if lacking on the stems) [inflorescences

usually dichotomously branched] Cnidosculus spp.

lib. Stinging hairs absent 12

12a. Trees with broad (8-30 cm) leaves and short (1-5 cm) triangular obtuse lobes, depth of

sinuses between lobes < 25% of the blade length 13

1 2b. Herbs, shrubs, small trees, or vines, leaves small to broad (3-25 cm) and with narrow lobes,

depth of sinuses > 30% of the length of the blade 14

1 3a. Apex of the petiole with prominent glands, stellate and scurfy hairs present; native

forest trees . . . Croton smithianus

BURGER & HUFT: FLORA COSTARICENSIS

1 3b. Apex of the petiole without prominent glands, plants glabrous or with simple or scurfy

hairs; introduced trees Aleurites spp.

14a. Stems with stellate hairs; inflorescences lacking lateral branches; herbs to 1 m tall; leaf blades

3-9 cm long Croton lobatus

14b. Stems lacking stellate hairs, glabrous or with glandular hairs; inflorescences often with short

lateral branches; herbs, shrubs, small trees, or vines, leaf blades 5-25 cm long 15

15a. Stems usually glabrous or with hairs less than 0.3 mm long; flowers with a single perianth-

like whorl, united in the lower part in <3 flowers; small shrubs, small trees, or vines

Manihot spp.

1 5b. Stems usually puberulent, often with gland-tipped hairs; flowers with 2 whorls of free sepals

and petals; herbs, shrubs, or trees Jatropha spp.

1 6a. (from 1 b) Plants slender vines with twining branches, shrubs with clambering green stems or woody

lianas, stems becoming > 1 m long, leaves > 4 cm long 17

1 6b. Plants erect herbs, trees, and shrubs, or if prostrate or procumbent and clambering then the stems

< 1 m long with leaves usually < 3 cm long 21

1 7a. Plants becoming woody lianas with stems usually > 4 mm thick [inflorescences 1 5-50 cm

long, paniculate; leaves often subcoriaceous, 6-24 cm long, palmately veined; stinging hairs

absent] Omphalea diandra

17b. Plants not becoming thick-stemmed woody lianas, leafy stems usually < 4 mm thick ... 18

1 8a. Shrubby plants with clambering terete green branches ca. 3-10 mm thick, sap white; stinging

hairs absent; flowers (= pseudanthia) bilaterally symmetrical and shoe-shaped, orange or red

[gardens and seasonally dry habitats] Pedilanthus

1 8b. Vines, not shrub-like, climbing leafy stems usually < 4 mm thick; flowers not shoe-shaped

19

19a. Inflorescences flower-like with 2 prominent bracts usually held in a vertical plane and en-

closing unusual flowers; venation palmate [stinging hairs sometimes present]

Dalechampia spp.

19b. Inflorescences not flower-like, bracts not large (> 5 mm wide) or opposite in a single plane;

venation palmate or pinnate 20

20a. Stinging hairs usually present; inflorescences terminal or leaf-opposed, with 1 or 2 slender

unbranched axes; styles united only at base, fruit usually 3-locular Tragia spp.

20b. Stinging hairs absent; inflorescences axillary or terminal with 1 stiff rachis; styles united into

a thick column, fruit usually 4-locular Plukenetia spp.

2 la. (from 1 6b) Leaf blades consistently < 5 cm long 22

2 1 b. Larger leaf blades > 5 cm long 27

22a. Leaf blades consistently opposite along the stems 23

22b. Leaf blades alternate along the stems, but sometimes opposite below the inflorescences and/

or at branching nodes 24

23a. Leaf blades usually strongly asymmetrical (unequal) at the base, often very small (5-

1 5 mm) stipules laciniate to ovate; plants erect or prostrate, herbs and subshrubs . . .

Chamaesyce spp.

23b. Leaf blades symmetrical (equal) at the base, usually > 10 mm long; stipules usually

poorly developed; plants erect herbs, shrubs, or trees Euphorbia spp.

24a. Fruits with 2 seeds/locule, seeds wedge-shaped and acutely triangular in cross-section; flowers

few from the leaf axils, subtending bracts inconspicuous; leaf blades often in a single plane,

very small to large (5-50 mm long) [note that cultivated ornamental shrubs with rounded

variegated leaves keying here are Breynia disticha] Phyllanthus spp.

24b. Fruits with 1 seed/locule, seeds rounded or angular in cross-section; flowers few to many,

axillary, terminal or extra-axillary, usually with conspicuous bracts; leaves usually in a spiral,

rarely < 1 5 mm long 25

25a. Stems slender and repent; herbs at high (2000-3000 m) elevation [leaves ovate-orbicular

with rounded crenate margins] Dysopsis glechomoides

25b. Stems not slender and creeping, mostly erect; plants rarely found above 2000 m elevation

. 26

FIELDIANA: BOTANY

26a. Male spikes leaf-opposed; female flowers often on stems between the nodes; fruits subtended

by sepals with scale-like processes on the outer surfaces; small-leaved herbs, rarely collected

in Central America Sebastiania corniculata

26b. Plants without the above characteristics 27

27a. (from 2 Ib and 26b) Weak-stemmed herbs and subshrubs 28

27b. Shrubs and trees with strong erect woody stems 32

28a. Leaf blades entire, glabrous or with thin inconspicuous hairs; sap often whitish; flowers

(actually pseudanthia) with calyx-like cup; pistil borne on an articulated stipe within the cup

Euphorbia spp.

28b. Leaf blades serrate to crenate, densely pubescent when subentire; sap rarely whitish; flowers

without calyx cups or urceolate perianth tube; pistils sessile 29

29a. Inflorescences terminal and spicate, resembling a foxtail or Cenchrus inflorescence, or the 2

flowers subtended by broadly rounded bracts with toothed margins and enlarging in fruit;

style branches usually much divided and laciniate Acalypha spp.

29b. Inflorescences not resembling foxtails, bracts subtending the fruit not broadly rounded and

exceeding the fruit in size; style branches not laciniate 30

30a. Plant usually growing in water or at the edge of wet sites, main stems usually hollow; venation

pinnate with 5-20 pairs of 2° veins [petioles without stalked glands or stipels at the apex,

base of blade without glands, blades ovate to linear-lanceolate] Caperonia spp.

30b. Plants not usually growing in or near water, main stems solid; venation usually palmate with

fewer than 6 pairs of 2° veins 31

3 la. Stellate or peltate hairs often present, simple hairs not attached at the center when present;

stalked glands often present at apex of the petiole; $ flowers with stamens inflexed in bud

Croton spp.

3 1 b. Hairs attached at the center but often appearing simple and appressed, stellate and peltate

hairs absent, stipel-like structures usually present at the apex of the petiole; $ flowers with

stamens straight in bud Argythamnia guatemalensis

32a. (from 27b) Ornamental small trees and shrubs cultivated in gardens and parks; leaves green to

red, purple, yellowish, or whitish; some with thick succulent green stems 33

32b. Plants not grown as ornamentals, wild species but sometimes used as hedges; leaves not brightly

colored; none with thick succulent green stems 39

33a. Leaf blades distinctly serrate, often reddish to copper colored; inflorescences pendant, to 40

cm long with reddish fimbriate style branches Acalypha spp.

33b. Leaf blades entire to subentire, green to purple, yellow, marked with white or leaves absent

and the stems green 34

34a. Leaf blades usually 3-5 times longer than wide, often variegated with yellow, green, white,

and purple, margins often undulate, sinuate, or minutely denticulate [few-branched shrubs]

35

34b. Leaf blades 1-3 times longer than wide, variegated leaves present or absent, margins entire

or sinuate 36

35a. Stems woody and without white sap; leaf blades subcoriaceous; inflorescences un-

branched and yellowish Codiaeum variegatum

35b. Stems semisucculent and with whitish sap; leaf blades slightly succulent; inflorescences

with dichotomous branches, reddish Synadenium grantii

36a. Fruits sweet fleshy drupes, 1 -seeded; leaves subcoriaceous and entire; sap not white or caustic;

shrubs or subshrubs Antidesma bunius

36b. Fruits dry capsules, usually 3-seeded; leaves thin to semisucculent; sap often white and caustic;

shrubs, trees, or green-stemmed vines and succulents 37

37a. Flowers (actually cyathia) shoe-shaped and bilaterally symmetrical, reddish or orange [petals

absent; distal stems green and terete and often clambering; plants to 2 m tall]

Pedilanthus spp.

37b. Flowers not shoe-shaped, radially symmetrical, white, yellow, red, or greenish 38

38a. Flowers (actually cyathia) urceolate or campanulate, greenish to yellow or red, petal-like

BURGER & HUFT: FLORA COSTARICENSIS

appendages small or absent; distal stems green and terete or woody; some plants resembling

cacti, others leafy trees and shrubs Euphorbia spp.

38b. Flowers with separate petals and sepals, not urceolate or campanulate, petals often large and

colorful; small trees and shrubs, not cactus-like Jatropha spp.

39a. (from 32b) Larger leaf blades rounded at the base and cordate to subcordate 40

39b. Larger leaf blades acute to obtuse or truncated at the base, not cordate or subcordate 44

40a. Plants becoming large trees with broad-based conical spines on the grayish trunk; fruit ca. 6

cm diam. with ca. 15 locules and seeds; staminal column with 2 (3) whorls of sessile anthers

Hura crepitans

40b. Plants shrubs or small to large trees, trunks lacking spines; fruits < 3 cm diam. with ca. 3

locules and seeds; stamens not united into a single column with whorled anthers 41

4 la. Style branches much divided and fimbriate; $ flower buds < 1 mm diam., anthers < 0.2

mm wide; fruits often subtended by a large broad bract Acalypha spp.

41b. Style branches simple to 2 times bifid, not fimbriate or laciniate; $ flower buds ca. 2 mm

diam., anthers > 0.2 mm wide; fruits not subtended by a broad bract 42

42a. Stamens incurved in bud, mostly 8-30/flower; petioles usually with stalked glands at apex;

stellate, scurfy or peltate hairs often present; inflorescences always with a single unbranched

rachis Croton spp.

42b. Stamens straight in bud, 3-5 or 30-60/flower; petioles without stalked glands at apex but

stipels may be present; hairs simple or stellate; inflorescences unbranched or paniculate . .

43

43a. Minute stellate hairs present on the leaf abaxially; $ flowers with 30-60 stamens; fruits fleshy

ca. 1 8 mm long, oblong; tall trees Conceveiba pleiostemona

43b. Small straight hairs present on the leaf surfaces; $ flowers with 3-5 stamens; fruits dry capsules

ca. 7 mm long; small trees Aparisthmium cordatum

44a. (from 39b) Leaf blades with palmate venation, the basal pair of lateral (2°) veins reaching the

middle or distal half of the blade 45

44b. Leaf blades with pinnate venation, the basal pair of lateral (2°) veins not reaching the distal half

of the blade 48

45a. Leaves usually tripliveined, the basal pair of veins strongly ascending and reaching the distal

third of the blade, midvein with only 1 pair of additional prominent 2° veins, pit domatia

often present in the vein axils [6 inflorescences unbranched; fruits ca. 4 mm diam.]

Alchorneopsis floribunda

45b. Leaves rarely tripliveined (except in Alchorned), the midvein usually with 2 or more pairs

of prominent 2° veins, pit domatia rarely present 46

46a. Style branches much divided and fimbriate; 3 flower buds < 1 mm diam., anthers < 0.2

mm long; fruits often subtended by a large broad bract Acalypha spp.

46b. Style branches simple to 2 times bifid, not fimbriate or laciniate; <3 flower buds 2-5 mm

diam., anthers > 0.3 mm long; fruits not subtended by a broad bract 47

47a. Stamens incurved in bud, 8-50/flower; fruits usually 3-locular; style branches usually 3-

many; inflorescences with a single unbranched rachis (except in C. billbergianus); petioles

often with stalked glands at apex; stellate, scurfy or peltate hairs often present

Croton spp.

47b. Stamens straight in bud, usually 8/flower; fruits usually 2-locular; style branches usually 2;

inflorescences unbranched or paniculate; petioles without stalked glands at apex but 2-6 flat

glands often present in the base of the blade; hairs simple or stellate Alchornea spp.

48a. (from 44b) Larger leaf blades with more than 10 major secondary veins on each side 49

48b. Larger leaf blades usually with fewer than 10 major secondary veins on each side 54

49a. Petioles with elevated glands along their length or at the apex (sometimes absent or at the

base of the blade, be sure to survey a number of leaves); flowers sessile or short-pedicellate

and the inflorescence spicate 50

49b. Petioles without elevated glands; flowers on prominent pedicels and the inflorescences rac-

emose 52

50a. Leaves narrowly obovate, 1 8-70 cm long [margin with conspicuous gland-tipped teeth];

10 FIELDIANA: BOTANY

hairs attached at the center; inflorescences axillary; <5 bracts small, 9 floral bracts with

glands ca. 1 mm diam Pausandra trianae

50b. Leaves oblong to elliptic oblong, 6-20 (rarely to 26) cm long; hairs attached at base or

leaves glabrous; inflorescences mostly terminal, floral bracts with broad rounded sessile

flat glands 1 .2-3 mm wide 51

5 la. Common trees; leaves 2-9 cm wide; leaf margin entire or rarely serrulate, the teeth

without prominent glands at their apex Sapium spp.

51b. Shrubs (rare in our area); leaves 0.7-3(-4) cm wide, leaf margins serrate with gland-

tipped teeth Stillingia zelayensis

52a. Flowers in dense cymes on dichotomously branching inflorescences or crowded in leaf axils;

flowers (pseudanthia) with calyx-like cup or tube; leaf margins always entire; small shrubs

to small trees Euphorbia spp.

52b. Flowers in open racemose inflorescences with a single unbranched rachis; flowers without a

cup-like or tubular calyx; leaf margins entire or dentate; shrubs to tall trees 53

53a. Trees and shrubs, usually with both $ and 2 flowers; inflorescences 10-40 cm long with many

closely crowded flowers; petals absent; anthers sessile on a conical receptacle; leaves usually

narrowly oblong, serrulate Mabea spp.

53b. Trees dioecious (unisexual); inflorescences 3-12 cm long with well-separated flowers; petals

present; anthers borne on slender filaments in <5 flowers; leaves usually elliptic-oblong, entire

Sagotia racemosa

54a. (from 48b) Styles much divided and laciniate, with slender filamentous divisions; fruit usually

subtended by broad serrate bracts; anthers usually < 0.2 mm wide; inflorescences usually narrow

spikes and racemes (the 9 inflorescence pyramidal-paniculate with slender lateral branches and the

fruit not subtended by broad bracts in A. costaricensis); trichomes of simple hairs attached at the

base; leaf margins serrate Acalypha spp.

54b. Styles not divided into slender filamentous divisions (except in Adelia with tufted domatia in leaf

axils); fruits not subtended by broad serrate bracts; anthers > 0.2 mm wide; inflorescences and

trichomes various; leaf blades entire to serrate 55

55a. Stalked or prominent glands usually present at the apex of the petiole or base of leaf blade; hairs

stellate, scurfy, peltate (flat and rounded) or simple; inflorescences with a single unbranched rachis;

$ flowers with well-developed perianth, the 8-40 stamens incurved in bud; 9 flowers with style

branches usually bifid or twice bifid; fruits dry 3-seeded capsules; seeds with a smooth surface and

apical caruncle Croton spp.

55b. Plants without the above suite of characteristics 56

56a. Young leafy stems or leaves with flat rounded hairs, the small (ca. 0.2 mm) appressed hairs (peltate

trichomes) often difficult to see [plants unisexual; fruits often with a slightly fleshy covering] 57

56b. Young leafy stems lacking flat appressed rounded hairs 58

57a. Fruits 3-6 mm long, with a single seed; inflorescences paniculate, usually with few spiciform

branches, never globose in bud Hyeronima spp.

57b. Fruits 12-14 mm long, with 3 seeds; inflorescences with few flowers from a short common

peduncule, at first enclosed in rounded bracts and resembling a flower bud . . Pera arborea

58a. Petioles with raised glands at the apex or along their length, or with raised glands at the base of

the blade 59

58b. Petioles without raised glands, flat or rounded glands sometimes present at the base of the blade

or along the blade margins 63

59a. Flowers borne on long (8-50 mm) thin pedicels from the axils of leaves [leaves entire and

ovate-rhombic; rarely collected in Costa Rica] Astrocasia tremula

59b. Flowers borne on axes of inflorescences, flowers sessile or on short thick pedicels [often

associated with 2 glands; 6 flowers with 2-3 stamens but the flowers often crowded and

difficult to interpret] 60

60a. Leaves glabrous or with appressed straight hairs attached at the middle; plants unisexual

(dioecious); flower groups often on short (1-3 mm) lateral peduncles [inflorescences with

floral glands not appressed on the rachis; fruits capsules] Tetrorchidium spp.

BURGER & HUFT: FLORA COSTARICENSIS 1 1

60b. Leaves usually glabrous, hairs attached at the base if present; plants bisexual (monoecious);

flower groups usually sessile or subsessile on the rachis 61

6 1 a. Fruits fleshy and green, usually with more than 4 seeds; sap highly caustic; leaf blades rounded-

ovate; trees of ocean shores and swamps Hippomane mancinella

61b. Fruits dry capsules with 3 or fewer seeds; sap not caustic; leaf blades ellipsoid to oblong;

trees of varied habitats 62

62a. Glands on the petiole apex or in the middle, prominent and easily seen; floral glands flat,

1.5-3 mm long, rounded and appressed on the inflorescence rachis; leaves mostly thick and

oblong Sapium spp.

62b. Glands at the base of the blade small and often difficult to see; floral glands less than 1 mm

diam., borne on the floral bracts; leaves mostly thin and elliptic . . Sebastiania pavoniana

63a. Leaf blades entire, the margins entire and lacking glands 64

63b. Leaf blades minutely serrate to conspicuously dentate or rounded-crenate, with well-defined glands

along the margin if subentire 72

64a. Petiole distinctly thickened below the blade for 4-8 mm and terete [inflorescences of 1-few

terminal flowers; $ flowers ca. 3 cm wide with many stamens; fruits 3—4 cm diam.; seasonally

dry forests] Garcia nutans

64b. Petioles without a prolonged thickened terete area beneath the blade, a short thickened area

at the apex of the petiole sometimes present 65

65a. Leaf blades with a notch (indentation) and terminal gland at the apex [blades elliptic-oblong

with a narrowed apex; inflorescences terminal with a few thick spiciform branches; rarely

collected in southern Central America] Caryodendron angustifoliwn

65b. Leaf blades lacking a notch and terminal gland at the apex 66

66a. Fruits 1 -seeded and with a thin fleshy cover; unisexual (dioecious) trees [ovary with 2 ovules/

locule but only 1 ovule developing; leaves subcoriaceous] 67

66b. Fruits usually 3-seeded, dry or with a thin fleshy covering; unisexual or bisexual, trees or

shrubs 68

67a. Leaf blades elliptic to oblong, often asymmetric at the base; flowers borne in leaf axils

on short or long pedicels; fruits axillary, seeds without a red or orange aril

Drypetes spp.

67b. Leaf blades often obovate, symmetric at the base; flowers and fruits borne on spikes

or racemes with thick axes; pedicels short or flowers sessile; seeds with red or orange

aril Richeria obovata

68a. Ovules 2 in each locule, fruits usually with 4-6 seeds; leaves usually distichous; flowers on

thin pedicels in axillary fascicles 69

68b. Ovules 1 in each locule, fruits usually 2-3-seeded; leaves usually in a spiral; flowers borne

on short racemes, in cymose groups, or in axillary fascicles 70

69a. Plants unisexual (dioecious); leaves deciduous; $ flowers with 4 stamens; fruits 9-12

mm diam., seeds 3-5 mm long, with fleshy bluish covering; a common species

Margaritaria nobilis

69b. Plants bisexual; leaves evergreen; <5 flowers with 3 stamens; fruits ca. 8 mm diam., seeds

ca. 7 mm long, without a fleshy covering; rarely collected Phyllanthus skutchii

70a. Flowers without perianth, borne on short (4 cm) unbranched axillary racemes [leaves narrowly

obovate and subcoriaceous] Actinostemon caribaeus

70b. Flowers with 4-5 sepals, or with a cupulate or urceolate base resembling a calyx cup ..71

7 la. Flowers with 4-5 distinct sepals, without a calyx cup; flowers borne in axillary fascicles; fruits

pendulous on long slender pedicels; leaves with tufted domatia in vein axils beneath

Adelia triloba

7 1 b. Flowers (pseudanthia) with a cupulate or urceolate base resembling a calyx cup, usually borne

in cymes; fruit never pendulous on long pedicels; leaves without tufted domatia in vein axils

Euphorbia spp.

72a. (from 63b) Stipules persisting, triangular to lanceolate, with 3-7 prominent raised veins parallel

with the midrib; stinging hairs present or absent 73

12 FIELDIANA: BOTANY

72b. Stipules caducous or, if persisting, without prominent parallel venation; stinging hairs absent . .

74

73a. Shrubs or small treelets 1-7 m tall; leaves with prominent distal serrations, 8-18 cm long;

stinging hairs usually present on the anther tips and fruits and sometimes on the leaves . .

Acidoton nicaraguensis

73b. Small single-stemmed subshrubs to 1 m tall; leaves subentire to serrulate, 12-28 cm long;

stinging hairs usually absent Dalechampia spathulata

74a. Inflorescences 12—45 cm long, racemose with a single axis and long-pedicellate flowers; $ flowers

with subsessile anthers on a conical receptacle [leaf blades oblong to narrowly oblong]

Mabea occidentalis

74b. Inflorescences not 12-45 cm long and racemose; anthers on a dome-shaped conical androecium

only in Cleidion (with inflorescences < 12 cm long) 75

75a. Leaves with small stellate hairs on the upper (adaxial) surface; $ inflorescences with overlapping

pubescent bracts, catkin-like in leaf axils [fruits 7xll mm; leaf blades 3-12 cm long]

Bernardia nicaraguensis

75b. Leaves glabrous on the upper surface or with few simple hairs; $ inflorescences of congested flowers

in sessile glomerules on slender spikes 76

76a. Leaves with petioles 13-50 mm long, distinctly thickened at the apex and often slightly bent [leaf

margins with prominent gland-tipped teeth] 77

76b. Leaves with petioles 4-16 mm long, not clearly thickened or bent at the apex [$ flowers usually

with 3 stamens] 78

77a. Styles usually 2 and simple; fruits with usually 2 seeds and fleshy exterior; 6 flowers usually

with 8 stamens; young stems glabrous Alchornea spp.

77b. Styles usually 3 and bifid; fruits dry capsules with usually 3 seeds; $ flowers with ca. 30

stamens on a conical receptacle; young stems minutely puberulent

Cleidion castaneifolium

78a. Leaves 12-33 cm long, often oblanceolate; plants unisexual; $ flowers with 3 sepals, 2 flowers with

6 sepals in 2 whorls, style branches broad Adenophaedra grandifolia

78b. Leaves 6-16(-20) cm long, usually obovate; plants usually bisexual; flowers with 0-2 bract-like

perianth parts, style branches slender Gymnanthes riparia

BURGER & HUFT: FLORA COSTARICENSIS 13

Manihot aesculifolia

FIG. 1 . Shrubs or treelets with deeply lobed leaves: species of Manihot and Ricinus.

14

FIELDIANA: BOTANY

Cnidoscolus

aconitifolius

FIG. 2. Vines and subshrubs with lobed leaves: species of Croton, Cnidoscolus, and Tragia.

BURGER & HUFT: FLORA COSTARICENSIS

15

J. curcas

FIG. 3. Trees and shrubs with deeply to slightly lobed leaves with palmate venation: species ofJatropha.

16

FIELDIANA: BOTANY

I 10cm

FIG. 4. Slender-stemmed vines with lobed or compound leaves: species of Dalechampia.

BURGER & HUFT: FLORA COSTARICENSIS

17

Tragia volubilis

Tr. correae

Tragia bailloniana

Dalechampia

>

heteromorpha

FIG. 5. Slender-stemmed vines: species of Dalechampia, Plukenetia, and Tragia.

18

FIELDIANA: BOTANY

Cnamaesyce serpens

Chamaesyce thymifolia

5 mm

Chamaesyce dioica

FIG. 6. Plants with very small leaves: species of Chamaesyce and Euphorbia.

BURGER & HUFT: FLORA COSTARICENSIS

19

Chamaesyce bahiensis

C. mesembrianthemifolia

FIG. 7. Plants with small opposite leaves: species of Chamaesyce.

20

FIELDIANA: BOTANY

Phyllanthus

stipulatus

Phyllanthus amarus

P. niruri

Phyllanthus

hyssopifolioides

1 mm

P. compressus

P. caroliniensis

FIG. 8. Plants with small alternate leaves: species of Phyllanthus.

BURGER & HUFT: FLORA COSTARICENSIS

21

Phyllanthus valerii

P. mocinianus

P. mocinianus s.l.

(P. anisolobus s.s.)

FIG. 9. Plants with small alternate leaves: species of Phyllanthus.

22

FIELDIANA: BOTANY

Dysopsis glechomoides

10 cm

Caperonia

castaneifolia

FIG. 10. Herbaceous or weedy plants: species of Caperonia, Croton, and Dysopsis.

BURGER & HUFT: FLORA COSTARICENSIS

23

Sebastiania corniculata

Argythamnia

guatemalensis

FIG. 1 1. Herbaceous or weedy plants: species ofAcalypha, Argythamnia, and Sebastiania.

24

FIELDIANA: BOTANY

Bernardia

Acidoton

nicaraguen'sis

Alchornea

costaricensis

Cleidion

castaneifolium

FIG. 12. Trees and shrubs with serrate elliptic leaves: species of Acidoton, Alchornea, Bernardia, Cleidion, Croton,

and Gymnanthes.

BURGER & HUFT: FLORA COSTARICENSIS

25

Pausandra

trianae

Adenopnaedra

grandifolia

Dalechampia

spathulata

FIG. 13. Plants with larger oblanceolate serrate leaves: species of Adenophaedra, Dalechampia, and Pausandra.

26

FIELDIANA: BOTANY

FIG. 14. Shrubs or herbs with serrate leaves and laciniate styles: species of Acalypha.

BURGER & HUFT: FLORA COSTARICENSIS

27

Acalypha

macrostachya

A. costaricensis

FIG. 15. Shrubs with serrate leaves and laciniate styles: species of Acalypha.

28

FIELDIANA: BOTANY

C. yucatanensis

FIG. 16. Plants with slightly serrate leaves and stellate hairs: species of Croton.

BURGER & HUFT: FLORA COSTARICENSIS

29

FIG. 1 7. Trees and shrubs with flat peltate hairs: species of Croton.

30

FIELDIANA: BOTANY

Croton xalapensis

FIG. 18. Trees and shrubs with larger ovate leaves, stellate hairs, and glands at apex of petiole: species of Croton.

BURGER & HUFT: FLORA COSTARICENSIS

31

Croton tenuicaudatus

5 mm

FIG. 19. Trees and shrubs with larger ovate or oblong leaves and stellate or peltate hairs: species of Croton.

32

FTELDIANA: BOTANY

Aparisthmium

cordatum

Conceveiba

pleiostemona

Tetrorchidium

euryphyllum

FIG. 20. Trees with larger leaves: species of Aparisthmium, Conceveiba, Sagotia, and Tetrorchidium.

BURGER & HUFT: FLORA COSTARICENSIS 33

Tetrorchidium

euryphyllum

FIG. 2 1 . Trees with glands on petioles or a thickened petiole apex: species of Garcia and Tetrorchidium.

34

FIELDIANA: BOTANY

Sapium glandulosum

sensu lato

FIG. 22. Trees with glands on petioles: species of Sapium.

BURGER & HUFT: FLORA COSTARICENSIS

35

Sapium glandulosum

(montane forms)

Sapium

rigidifoiium

10 cm

FIG. 23. Trees with glands on petioles (Sapium spp.) or shrubs with glands along lamina margins (Stillingia sp.).

36

FIELDIANA: BOTANY

Alchorneopsis floribunda

FIG. 24. Trees with slightly serrate leaves and subpalmate or palmate venation: species of Alchornea and Al-

chorneopsis.

BURGER & HUFT: FLORA COSTARICENSIS

37

Sebastiania pavoniana

Actinostemon caribaeus

Margaritaria nobilis

FIG. 25. Trees and shrubs with entire or subserrate leaves: species of Actinostemon, Margaritaria, Phyllanthus,

and Sebastiania.

38

FIELDIANA: BOTANY

Gymnanthes lucida

Gymnanthes riparia

FIG. 26. Trees and shrubs with entire elliptic leaves: species of Gymnanthes, Mabea, and Pera.

BURGER & HUFT: FLORA COSTARICENSIS

39

Drypetes

standleyi

UB

Drypetes

brownii

Amanoa

guianensis

FIG. 27. Trees and shrubs with entire elliptic leaves: species of Amanoa and Drypetes.

40

FIELDIANA: BOTANY

Hyeronima

alchorneoides

FIG. 28. Trees with spicate inflorescences or inflorescence branches: species of Hyeronima and Richeria.

BURGER & HUFT: FLORA COSTARICENSIS

41

Euphorbia

heterophylla

UB

Euphorbia

oerstediana

FIG. 29. Herbs or weak-stemmed shrubs with entire leaves and white sap: species of Euphorbia.

42

FIELDIANA: BOTANY

Euphorbia

hoffmanniana

Euphorbia

colletioides

Euphorbia

schlechtendalii

GJB

FIG. 30. Shrubs and trees with small entire leaves and white sap: species of Euphorbia.

BURGER & HUFT: FLORA COSTARICENSIS

43

Plukenetia

penninervia

Adelia triloba

cm

FIG. 31. Climbers and unusual plants: species of Adelia, Mabea, Omphalea, and Plukenetia.

FIELDIANA: BOTANY

Hippomane mancinella

Codiaeum vanegatum

FIG. 32. Trees and shrubs with distinctive leaves: species of Astrocasia, Codiaeum, Hippomane, and Hura.

BURGER & HUFT: FLORA COSTARICENSIS

45

Descriptions of Genera and Species

Acalypha Linnaeus

REFERENCE— O. Seberg, Taxonomy and phylog-

eny of the genus Acalypha (Euphorbiaceae) in the

Galapagos Archipelago. Nord. J. Bot. 4: 159-190.

1984.

Annual or perennial herbs, shrubs or small trees, mo-

noecious or less often dioecious, hairs simple or stellate

(plants rarely glabrous); stipules paired at the leaf base,

ovate to lanceolate or linear, (l-)3-7- veined, often with

linear distal awn. Leaves alternate, simple, petiolate,

glands absent at apex of petiole (stipels rarely present);

leaf blades mostly ovate, palmately 3-5-veined or pin-

nately veined, pubescent or glabrous, margins crenate-

serrate or dentate (not lobed). Inflorescences terminal or

axillary, unisexual or bisexual, solitary, the 3 axillary

(often below the 9) usually spiciform and slender with

flowers in sessile clusters; 2 inflorescences axillary or

terminal, open paniculate to spicate or racemose, bisex-

ual spikes usually with 9 flowers proximal and <5 distal,

floral bracts broadly sessile, often enlarging and enclosing

the fruit; 9 flowers sessile or short-pedicellate. Male flow-

ers very small, pedicellate, globose in bud, calyx 4-parted,

valvate in bud, petals absent, disk absent, stamens 8 (4,

-16), borne on a slightly raised receptacle, filaments free,

anthers with divaricate or pendulous thecae, oblong or

linear to vermiform; pistillode absent. Female flowers

with 3-5 sepals, united at or near the base, imbricate or

open in bud, shorter than the pistil, petals absent, stam-

inodes absent, disk absent; ovary 3-(2-)locular, surface

often muricate, pubescent or papillate, ovules 1/locule,

style column short, each style with many slender lacin-

iate style branches (unbranched in A. alopecuroided).

Fruits capsular, usually small, 3-lobed and breaking into

3 2-valved 1 -seeded cocci, bracts enlarging in fruit (in

most species) to envelop the capsule; seeds small, ellip-

soid to subglobose, caruncle minute or absent, testa crus-

taceous, endosperm fleshy or granular, cotyledons broad

and flat.

A pantropical genus of 400-500 species with a

few species reaching temperate regions. The ma-

jority of species are Neotropical and are in serious

need of monographic study. Many species are

weedy plants of open sites that vary greatly from

individual to individual. This large intraspecific

variation has made understanding the species-

boundaries and the search for important taxonom-

ic characters difficult. Fortunately, southern Cen-

tral America has relatively few species as com-

pared to Mexico or South America. As in many

other genera, the weedy species are often poorly

represented in herbaria. These plants often resem-

ble species of Urticaceae.

Acalypha is recognized by its often long narrow

spiciform, usually unisexual, inflorescences, very

small $ flowers with minute anthers, 9 flowers with

much-divided and slender-laciniate style branches

often red or purple, broad floral bracts enlarging

to enclose the fruits (in most species) and small

three-seeded capsules. The <5 inflorescences are al-

ways axillary. Specimens lacking mature 2 flowers

and fruits may be very difficult to identify.

Key to the Species of Acalypha in Costa Rica

la. Plants of gardens and hedgerows, with brightly colored leaves or inflorescences 2

Ib. Plants of natural and disturbed vegetation, not grown for the colorful leaves or inflorescences 3

2a. Plants with conspicuous reddish pendant inflorescences, $ inflorescences usually absent; leaves

usually green A. hispida

2b. Plants with inconspicuous $ and 2 inflorescences often present on the same plant; leaves

usually red to purple A. amentacea ssp. wilkesiana

3a. 2 flowers and fruits pedicellate along the major inflorescence axes, bracts of 2 flowers remaining

small and obscure; leaves > 1 2 cm long and palmately veined; species of evergreen areas below

800 m elevation 4

3b. 2 flowers and fruits sessile (solitary 2 flowers sometimes borne on long axillary pedicels in A.

arvensis and A. leptopodd), bracts of 2 flowers enlarging and enveloping the fruits but sometimes

difficult to see because of the pubescence (only enlarging slightly in A. radinostachyd); leaves larger

or smaller, venation palmate or pinnate; species of evergreen and deciduous areas from sea level

to 2200 m elevation 5

4a. Plants usually with 2 flowers in large terminal many-branched narrowly pyramidal panicles;

seeds 1.5-1.7 mm long; leaf blades becoming narrower in the lower Vj-'A, rarely ovate,

venation pinnate A. costaricensis

4b. Plants with the 2 flowers usually on slender axillary unbranched racemes; seeds 0.8-1.4 mm

46

FIELDIANA: BOTANY

long; leaf blades nearly always broadest in the lowest '/3 and ovate, venation palmate or

subpalmate A. villosa

5a. Leaves with pinnate venation, shrubs or small treelets 6

5b. Leaves with palmate or subpalmate venation (the basal pair of 2° veins prominent and terminating

at or above the middle of the blade), herbs, shrubs, or small treelets 8

6a. Leaf blades narrowed to an obtuse or acute base, only rarely slightly rounded at the petiole;

9 bracts becoming 2-4 mm long with small (< 1 mm) lobes or unlobed in fruit; seeds 1.4-

1.6 mm long [9 flowers few, axillary or at base of <3 spikes] A. diversifolia

6b. Leaf blades narrowed to the base and slightly rounded or auriculate at the petiole; 9 bracts

becoming 10-13 mm long with teeth 1-6 mm long in fruit; seeds 2.1-2.6 mm long ... 7

7a. Female flowers many in long (to 1 8 cm) conspicuous terminal inflorescences; <3 inflorescences

few A. ferdinandii

7b. Female flowers 1-few, in axils of distal leaves; $ inflorescences many A. apodanthes

8a. (from 5b) Plants shrubs or trees, > 1 m tall; 9 bracts with lobes becoming up to 2 mm long; glands

often present at the apex of the petiole 9

8b. Plants herbaceous, usually < 1 m tall; <5 bracts with lobes often 3-7 mm long (except/!, mexicand);

glands rarely present at the apex of the petioles 13

9a. Fruiting inflorescence a slender (0.2 mm thick) pendulous rachis with usually only a single

terminal bract, to 4 cm long (axillary 9 flowers may also be present) [stipules 4-15 mm long

with a long-awned tip] A. leptopoda

9b. Fruiting inflorescences with rachis 0.5-2.5 mm thick, with many bracts and fruits along the

rachis, to 30 cm long 10

1 Oa. Bracts of the 9 inflorescence 2-3 mm long and not enlarging in fruit; stipule scars becoming

thickened, hard and pale colored, 2-3 mm wide [stipules to 7 mm long with a narrowed

terminal portion; 9 inflorescences terminal and solitary; plants of the Caribbean slope, 100-

300 m] A. radinostachya

1 Ob. Bracts of the 9 inflorescences enlarging (to 6 mm long) in fruit; stipule scars not as above

11

1 la. Stipules ovate to narrowly lanceolate, without a slender terminal awn; petioles 2-26 cm long;

fruiting inflorescences axillary, to 35 cm long, pendant (see also A. obtusifolia); common and

widespread A. macrostachya

1 Ib. Stipules narrowed above the base into a long slender (0.3 mm) awn; petioles 2-13 cm long;

fruiting inflorescences terminal, to 1 8 cm long, erect; rarely collected species 12

1 2a. Leaf blades ovate, petioles to 7 cm long; margins of fruiting bracts with prominent

teeth, without gland-tipped hairs; semideciduous forests at 100-800 m elevation . . .

A. schiedeana

1 2b. Leaf blades elliptic, petioles to 1 3 cm long; margins of fruiting bracts entire and with

gland-tipped hairs to 1.5 mm long; evergreen forest at 1 100 m

A. sp. aff. A. mortoniana

1 3a. (from 8b) Large-bracted 9 inflorescences present at nearly all nodes, usually short and subsessile

(rarely to 4 cm long), bracts ca. 4 mm long with short (0.5 mm) rounded lobes [rarely collected,

900-2200 m elevation] A. mexicana

13b. Large-bracted 9 inflorescences only at the distal nodes; 9 bracts with lobes 1-6 mm long 14

14a. Fruiting inflorescences 10-15 mm wide, open or densely flowered and resembling the hairy spikes

of a foxtail grass (Setaria spp.) [9 bracts with linear lobes 3-6 mm long, glabrous or with thin

straight hairs 1-2 mm long] 15

14b. Fruiting inflorescences 5-12 mm wide, not resembling the hairy inflorescences of a foxtail grass

17

1 5a. Flowering and fruiting 9 spikes with bracts not closely congested, bracts glabrous to very

minutely puberulent or with few glandular hairs; larger leaf blades > 8 cm long; seeds > 2

mm long [uncommon in Costa Rica] A. polystachya

1 5b. Flowering and fruiting 9 spikes with bracts closely congested, bracts with thin straight hairs

to 2 mm long; leaf blades to 8 cm long; seeds < 1 .5 mm long 16

1 6a. Plants lacking gland-tipped hairs on stems but gland-tipped hair often present in the inflo-

BURGER & HUFT: FLORA COSTARICENSIS 47

rescence; stipules to 5 mm long; 2 inflorescences axillary on peduncles to 32 mm long; styles

with 3-5 branches and bright red (absent in later fruiting stages); seeds 1.1-1.4 mm long;

common in Costa Rica A. arvensis

16b. Plants usually with gland-tipped hairs on stems, petioles and/or inflorescences; stipules to

2.5 mm long; 9 inflorescences consistently terminal on peduncles to 10 mm long, styles

unbranched and difficult to see; seeds 1-1.1 mm long; uncommon in Costa Rica

A. alopecuroides

17a. 2 flowers few and axillary or lacking, distal 5 flower often on a slender (0.2 mm) rachis 0.5-3 cm

long; stipules often terminating in a slender transparent sharp-pointed hair; immature plants of

A. arvensis

17b. 9 flowers on spicate inflorescences, distal 2 flower not borne on a slender filament-like rachis;

stipules not terminating in a long, sharp slender hair 18

18a. Stems and leaves with many thin straight hairs 1-2 mm long; <? spikes 5-12 cm long, with thin

peduncles 1-5 cm long [rarely collected in Central America] A. triloba

18b. Stems and leaves with short (0.1-0.4 mm) hairs; $ spikes 0.8-3 cm long, with peduncles < 5 mm

long 19

19a. Fruiting bracts with rounded or triangular lobes 1-2 mm long, with hairs ca. 1 mm long; stipules

triangular to subulate; 1 100-1900 m elevation A. septemloba

19b. Fruiting bracts with linear lobes to 6 mm long, glabrous or with minute hairs; stipules linear; 10-

1000 m elevation . . .A. setosa

Acalypha alopecuroides Jacq., Collect. 3: 196.

1790. Icon. PI. Rar. 3: 19, t. 620. 1792. Figure

11.

Herbs 20-90 cm tall, bisexual (monoecious), leafy stems

0.6-3 mm thick, densely pubescent with thin straight

hairs 0.2-1 mm long, also often with gland-tipped hairs

0.6-1.2 mm long; stipules 1-2.5 mm long, 0.3-0.6 mm

broad at the base, subulate-linear, sparsely puberulent,

persisting. Leaves with petioles 4-65(-80) mm long, 0.2-

0.5 mm thick, sparsely pubescent with thin hairs, gland-

tipped hairs usually present distally, small (0.3 m) dig-

itate glands sometimes present at the apex; leaf blades

1.8-8 cm long, 1.3-5.5 cm wide, ovate to ovate- trian-

gular, tapering to a short-acuminate apex, margins with

14-28 teeth/side, base rounded and truncate (rarely sub-

cordate), drying membranaceous, pubescent above with

scattered thin straight hairs 0.2-2 mm long, with shorter

hairs along the veins beneath, venation palmate, 2° veins

2-3/side of the midvein. Male inflorescences 8-30 mm

long, peduncles 2-6 mm long, 0. 1-0.2 mm thick, slender

and spiciform, gland-tipped hairs usually present, bracts

ca. 0.4 mm long, usually obscure; $ flower buds ca. 0.4

mm diam., glabrous, perianth 0.5 mm wide at anthesis.

Female inflorescences terminal, 1.5-6 cm long, flowering

portion becoming 8-15 mm wide and ellipsoid to cylin-

drical, peduncles 2-10 mm long, ca. 1 mm thick, bracts

with linear teeth 5-8 mm long, with straight thin hairs

to 2 mm long, gland-tipped hairs often present, some-

times with a slender distal rachis and solitary $ flower;

2 flowers 1 /bract, sessile, hispidulous and often with gland-

tipped hairs, styles 2-7 mm long, unbranched and in-

conspicuous. Fruits 1.2-1.5 mm diam., subtended and

enclosed by bracts to 12 mm long with a broad united

(4 mm) base and linear lobes 5-8 mm long; seeds 1-1.1

mm long, 0.6-0.7 mm diam., grayish, ovoid-ellipsoid,

caruncle slightly elevated, ca. 0.4 mm long, whitish.

Weedy plants of open sites in evergreen and

seasonally dry habitats in the Pacific lowlands, 0-

300 m elevation (to 1400 m in Guatemala). Flow-

ering and fruiting in July-August. While this spe-

cies can be locally common, collections from

southern Central America are few; it has not been

collected in the Caribbean lowlands or in the ev-

ergreen areas of the Pacific lowlands of Costa Rica.

This species ranges from the southern United States

and the Bahamas to Venezuela and Peru.

Acalypha alopecuroides is recognized by its small

weedy habit, presence of gland-tipped hairs, short

slender axillary $ spikes, bracts with long-linear

teeth, thick terminal catkin-like 2 spikes, and un-

divided styles. This species is very similar to A.

arvensis, and the two are very closely related. Nev-

ertheless, the two seem to differ quite consistently

by the characters used in the key. This species has

been called chimbombo in Costa Rica (Orozco 221

F).

Acalypha amentacea Roxb., Fl. Ind. ed. 1832, 3:

676. 1832, subspecies wilkesiana (Mull. Arg.)

Fosberg, Smithsonian Contr. Hot. 45: 10. 1980.

A. wilkesiana Mull. Arg. in DC., Prodr. 15 (2):

817. 1866.

Ornamental shrubs 2-5 m tall, monoecious, leafy stems

1.5-6 mm thick, sparsely to densely pubescent with mi-

nute (0.2 mm) appressed or curved hairs; stipules 10-

25 mm long, ca. 2 mm wide at the base, narrowly lan-

ceolate. Leaves with petioles 1 .2-9 cm long, 0.8-2.5 mm

48

FIELDIANA: BOTANY

thick, sparsely to densely puberulent; leaf blades 9-28

cm long, 4-18 cm wide, ovate to ovate-elliptic, apex

acuminate, margin with rounded teeth 22-60/side, base

obtuse to rounded and subcordate, drying chartaceous,

with few short hairs along the veins above, glabrescent

below, venation palmate, 2° veins 5-8/side of the mid-

vein. Inflorescences mostly axillary, $ inflorescences to

25 cm long, 2 inflorescences 4-14 cm long, bracts sub-

tending 2 flowers 1-4 mm long, with 1 central lobe and

smaller lateral lobes; style branches to 6 mm long.

Acalypha amentacea ssp. wilkesiana is a very

common ornamental shrub with foliage varying

from bronze-green to reddish purple or dark red

and marked with white or pink. Originally from

the western Pacific, the species is now widely

planted in gardens of the tropics and subtropics.

It is grown at low and middle elevations (0-1500

m) in Central America. Common names are capa

del rey, manto de Jesus, pastor, "beefsteak plant,"

"copper leaf," and "Jacob's coat."

Acalypha apodanthes Standl. & L. O. Williams,

Ceiba 1 : 24 1 . 1 95 1 . A.ferdinandii var. pubescens

K. Hoffm., Pflanzenreich 4. 147. 16: 64. 1924.

Figure 14.

Shrubs or small treelets 1.5-3(-6) m tall, mostly mo-

noecious, bark rough brown, leafy stems 1.2-3.5 mm

thick, densely pubescent with straight or curved hairs

0.2-0.6 mm long; stipules 3-8 mm long, 0.5-1 mm broad

at the base, narrowed ca. 1 mm above the base into a

linear awn, with minute appressed hairs. Leaves with

petioles 4-20(-32) mm long, 0.5-1 mm thick, usually

densely hirsute with erect hairs 0.2-0.4 mm long, flat or

disk-like glands sometimes present at the apex; leaf

blades 5-17 cm long, 1.5-5 cm wide, narrowly elliptic

to narrowly elliptic-oblong, oblanceolate or elliptic, ta-

pering gradually to an acuminate apex, margins with 20-

30 teeth/side ca. 0.5 mm long, tapering gradually to the

base and rounded (2-3 mm) at the petiole (subauricu-

late), sparsely pubescent above with hairs ca. 0.5 mm

long, more densely pubescent beneath with hairs 0.2-

0.4 mm long, 2° veins 7-12/side. Male inflorescences 2-

16 cm long, 1.5-2 mm diam., peduncles 4-10 mm long,

0.3-0.5 mm thick, densely pubescent, flower clusters ca.

1.4 mm wide, usually closely approximate, rachis 0.2-

0.4 mm thick, bracts ca. 0.6 mm long, acute; $ flowers

minute, buds ca. 0.4 mm diam., pedicels to 0.7 mm long.

Female inflorescences axillary to distal leaves, usually

only 1 bract/node with 1 2 flower, sometimes at the base

of a 3 spike, bracts 1-5 mm long and becoming 5-8 mm

long in fruit, with 7-1 1 prominent linear or triangular

teeth 3-6 mm long, flowers sessile; 2 flowers with ovary

ca. 1.3 mm long, densely covered with straight erect

hairs, style branches to 6 mm long, separate to base,

white to red. Fruits enclosed within the cupulate-con-

duplicate bracts, united base of bracts ca. 3 mm long;

seeds 2.1-2.2 mm long, 1.6-1.7 mm diam., oblong-

rounded.

Plants of evergreen forest formations of the Ca-

ribbean slope and adjacent areas, 100-1400 m el-

evation. Flowering in late January-September. The

species is only known from central and northern

Costa Rica (but see below).

Acalypha apodanthes is recognized by its soli-

tary 9 bracts in distal leaf axils, long slender 6

spikes, small narrow pinnately veined leaves with

small basal lobes (subauriculate), and larger seeds.

This species may prove to be an unusual mor-

photype of A.ferdinandii (q.v.), lacking the char-

acteristic terminal 2 spikes of A. ferdinandii and

usually with smaller leaves. The shared habitat (in

part) and the similar phenology also suggest that

these plants may be conspecific.

Acalypha arvensis Poeppig in Poeppig & Endl.,

Nov. gen. sp. pi. 3: 21. 1841. Figure 11.

Herbs 20-70 cm tall, older plants often with multiple

branches from a woody base, leafy stems 0.9-4 mm thick,

with thin whitish hairs 0.2-0.7(-1.5) mm long, smaller

hairs often recurved; stipules 2-5 mm long, 0.5 mm wide

at the base, narrowly lanceolate to subulate, often ter-

minated by a thin transparent sharp-tipped hair. Leaves

with petioles 1-3 cm long, 0.3-0.9 mm thick, sparsely

to densely pubescent, lacking glands at the apex; leaf

blades 1.8-7 cm long, 1.2-4 cm wide, ovate to ovate-

elliptic, tapering to an acute or short-acuminate apex,

margin with 1 1-23 teeth/side, cuneate to rounded and

truncate at the base, drying thin-chartaceous, pubescent

on both surfaces with thin straight hairs 0.2-1.9 mm

long, venation palmate, 2° veins 2-4/side along the mid-

vein. Male inflorescences 3-5 cm long, ca. 1 .5 mm thick,

peduncles 3-25 mm long, 0.2-0.3 mm thick, puberulent;

$ flowers pedicellate, perianth 0.4-0.5 mm broad at an-

thesis. Female inflorescences axillary, at first 4-7 mm

long with subglobose flowering portion but expanding

and 24-80 mm long in fruit, becoming a dense loosely

cylindrical spike 6-22 mm wide, sometimes with a distal

filiform rachis with several <5 flowers or 1-3 2 flowers,

peduncles 6-32 mm long, 0.4-1 mm thick, with thin

whitish hairs ca. 1 mm long (gland-tipped hairs present

or absent), bracts becoming 4-8 mm long with 3-7 lobes,

lobes triangular at base and with linear tips 3-5 mm

long; 2 flowers soon becoming enclosed within the con-

gested bracts, ovary ca. 0.7 mm long, hispidulous, style

branches 2-5 mm long, red. Fruits deeply 3-lobed, his-

pidulous, hidden within the expanded and persistent

bracts of the cylindrical infructescence; seeds 1.1-1.4

mm long, 0.7-1 mm diam., oblong-subglobose, surface

grayish and minutely reticulate (x 10), caruncle ca. 0.4

mm long and slightly elevated, whitish.

Common weedy plants of open or partly shaded

sites in evergreen and deciduous forest formations;

1-700 m elevation (ca. 1 100 m near San Vito and

in Chiriqui). Probably flowering primarily in the

wet season; fruiting mostly in July-November in

BURGER & HUFT: FLORA COSTARICENSIS

49

Costa Rica. The species ranges from Mexico to

Brazil and Bolivia.

Acalypha arvensis is recognized by its herba-

ceous habit, short-awned stipules, and the short

thick catkin-like infructescences. The infructes-

cences have a soft texture because of the thin hairs

and long linear lobes of the many imbricated bracts;

they are reminiscent ofCenchrus (Poaceae). Some

plants may also produce small 2 inflorescences with

one to three separate proximal 2 flowers and one

to two distal flowers on a filiform rachis. The ax-

illary inflorescences and lack of glandular hairs on

stems help separate this species from the closely

related A. alopecuroidea. Specimens with fruiting

infructescences are much more common than those

with flowers in anthesis.

Acalypha costaricensis (Kuntze) Knobl. ex Pax &

Hoffm., Pflanzenreich 4, 147, 16: 16. 1924. Ri-

cinocarpus costaricensis Kuntze, Rev. gen. pi. 2:

615. 1891. Figure 15.

Herbs or subshrubs 0.6-2(-4) m tall, monoecious or

dioecious, leafy stems 1.2-4.3 mm thick, with thin or

curved hairs 0.4-1 mm long, terete; stipules 2.5-8 mm

long, 1-1.3 mm wide at the base, lanceolate to linear,

glabrous or pubescent. Leaves with petioles 1.5-7 (-10)

cm long, 0.5-1 .8 mm thick, pubescent or rarely glabrous,

often with minute (0.5 mm) disk-like or ridged glands

at the blade; leaf blades 10-22 cm long, 4.5-1 1 cm wide,

elliptic to elliptic-oblong or ovate-elliptic, apex acumi-

nate with narrowed tip 8-15 mm long, margin crenate-

dentate with short (0.5-3 mm) teeth 1 2-28/side, rounded

at the truncated base or subcordate at the petiole, drying

thin-chartaceous and green, with few hairs ca. 0.6 mm

long above, more densely pubescent beneath with hairs

ca. 0.3 mm long, venation pinnate, 2° veins 5-10/side.

Male inflorescences 5-30 cm long, 1.5-3.5 mm wide,

peduncles 8-12 mm long, 0.3-0.4 mm thick, flower clus-

ters closely crowded or to 1.5 mm apart, 6 flower buds

ca. 0.8 mm diam. Female inflorescences terminal, 15-

40 cm long, 4-12 cm wide, paniculate and narrowly

pyramidal, peduncles to 1 1 cm long and 3 mm thick,

minutely pubescent, lateral branches 2-9 cm long (be-

coming shorter distally), 0.2-0.4 mm thick, subtended

by bracts ca. 1 mm long; flowers usually 1 /bract, sub-

tended by imbricate bracts ca. 0.5 mm long, pedicels 1-

5 mm long, ca. 0.2 mm thick, puberulent; $ flowers pur-

ple or dark red, sepals ca. 1 mm long, linear, ovary 1-

2.3 mm long, 1 .5 mm diam., verrucose hispidulous, style

column 0.5-1 mm long, style branches 2-4 mm long,

with many filamentous parts. Fruits 3-4 mm wide,

3-lobed, with erect narrow verrucose projections 0.2-0.4

mm high; seeds 1.5-1.7 mm long, 1.4-1.5 mm diam.,

subglobose or ovoid, smooth, brown or gray, caruncle

minute.

Plants of lowland Caribbean rain forest for-

mations, 20-250(-500) m elevation. (Of the 54

Costa Rican collections seen, only 1 was collected

above 250 m elevation.) Flowering and fruiting

throughout the year but collected mostly in Feb-

ruary-August. The species ranges from southern

Mexico to Panama.

Acalypha costaricensis is recognized by the large

open terminal 2 inflorescences with conspicuous

reddish purple laciniate styles. The larger long-

petiolate leaves, verrucose surface of the ovary,

and long narrow $ inflorescences are also distinc-

tive. It is a handsome and distinctive species. Be-

cause the very small bracts do not enlarge in fruit

and the 2 flowers are pedicellate, this species is

placed in subgenus Linostachys (as is A. villosa,

q.v.). This species resembles the rarely collected

Ayenia mastatalensis Cristobal & Zamora (Ster-

culiaceae).

Acalypha diversifolia Jacq., Hort. Schoenbr. 2: 63,

t. 244. 1792. A. leptostachya H.B.K., Nov. gen.

sp. 2: 96. 1 8 1 7. A. panamensis Klotzsch in Seem.,

Bot. voy. Herald 101. 1853. A. tabascensis Lun-

dell, Lloydia 4: 51. 1941. Figure 14.

Shrubs or small trees, 1.5-5(-15) m tall, monoecious,

with many arching branches, leafy stems 1-4 mm thick,

sparsely to densely hirsutulous with thin hairs 0.2-0.5

mm long, glabrate, gray to dark brown; stipules 3-6(-8)

mm long, 0.5-1 mm broad at the base, narrowed 1-2

mm above the base to the linear tip, minutely puberu-

lent, often with a thickened convex base. Leaves with

petioles 4-1 7(-30) mm long, 0.7-1.5 mm thick, sparsely

to densely pubescent, glabrescent, distal glands absent;

leaf blades 6-20 cm long, 2-8 cm wide, narrowly elliptic

to ovate-elliptic or oblong-lanceolate, apex short- to long-

acuminate, tip to 25 mm long, margins with 20-40 teeth/

side, 0-0.6 mm high, base obtuse to cuneate and often

slightly rounded at the petiole, drying chartaceous, upper

surfaces sparsely pubescent to glabrescent, lower surface

usually pubescent along the veins with hairs 0. 1-0.6 mm

long, 2° veins 4-8/side. Inflorescences axillary, spicate,

mostly 3 and 2-10 cm long (sometimes on short leafless

shoots forming a panicle of spikes), peduncles 0—4 mm

long, 0.4-0.7 mm thick, sparsely to densely puberulent,

9 bracts 1-3 and axillary or 1-3 near the base of bisexual

spikes, distal 6 portion of the spike 2-5 mm wide. Male

flowers in congested or separated clusters, bracts 0.5-1

mm long, triangular, pedicels 0.6-1 mm long, buds ca.

0.5 mm diam., calyx 0.8-1 mm wide, cupulate; stamen

cluster 0.5 mm wide distally, anthers ca. 0.1 mm long.

Female flowers 1-3/bract, subtending bracts 1-1.5 mm

long but hidden by pubescence, enlarging in fruit; ovary

0.9-1.5 mm long, ovoid and covered with short erect

hairs, base of styles 1-1.5 mm long with laciniate branch-

es to 4 mm long. Fruits 2x3 mm, muricate with scat-

tered short (0. 1 mm) hairs, subtended by bracts 2-4 mm

long, 3-4 mm broad, broadly ovate, lobes small or ab-

sent, subglabrous; seeds 1.4-1.6 mm long, ca. 1.2 mm

diam., oblong-rounded, dark brown, smooth.

Common plants of evergreen formations and

shaded sites in deciduous forest formations (often

50

FIELDIANA: BOTANY

found along riverbanks), 20-1100 m elevation.

Flowering in December-August (primarily Feb-

ruary-May); fruiting in March-July. This species

ranges from Mexico to Peru.

Acalypha diversifolia is recognized by the pin-

nately veined leaves lacking glands at the petiole/

blade juncture, dense <5 flowers often forming thick

(4-5 mm) spikes, few 9 flowers in leaf axils or at

base of rare bisexual spikes, and few fruit sub-

tended by subglabrous bracts lacking well-devel-

oped teeth. The paucity of 9 flowers and rarity of

fruit among the many collections of this common

Central American species is unusual. This may be

due to the late development of the difficult-to-see

axillary fruits. The species has been called "costilla

de caballo" and "costilla de danto" in Honduras.

Acalypha ferdinandii K. Hoffm., Pflanzenreich 4,

147. 16: 63. 1924. Figure 14.

Shrubs or subshrubs 0.7-3(-6) m tall, usually monoe-

cious, leafy stems 0.7-4 mm thick, with short (0.5 mm)

hairs or glabrous; stipules 3-11 mm long, ca. 1 mm wide

at the base, contracted 1-2 mm above the base into a

linear awn, glabrous or with thin appressed hairs 0.1-

0.2 mm long. Leaves with petioles 4-34(-60) mm long,

0.6-1.5 mm thick, glabrous or with few short hairs in

early stages (rarely densely pubescent), small glands or

pits sometimes present at the apex; leaf blades 6-22 cm

long, 2-9 cm wide, narrowly elliptic-obovate to oblan-

ceolate or elliptic, usually broadest at or above the mid-

dle, tapering gradually to the acuminate apex, serrations

1 1-35/side, 0.3-1 mm high, blade narrowed below the

middle, rounded at the petiole and often auriculate with

small (0-2 mm) basal lobes, drying chartaceous, gla-

brescent above, glabrous or with thin short (0.3-0.7 mm)

hairs beneath, 2° veins 7-10/side. Male inflorescences

axillary to distal leaves, 4-1 2 cm long, ca. 3^1 mm diam.,

yellow-green, peduncles 3-15 mm long, ca. 0.5 mm diam.

and glabrous or pubescent, flower clusters closely con-

gested; 6 flowers 0.6-1 mm wide, borne on pedicels 0.5-

1 mm long, anthers ca. 0.1 mm long. Female inflores-

cences terminal or near- terminal, 6-18 cm long and spi-

cate, 10-15 mm diam. (including style branches), red-

dish, bracts 5-8 mm long, subtending 1-3 sessile 9 flow-

ers, enlarging in fruit, teeth of the bracts 0.5-3 mm long,

acute; 9 flowers with ovary ca. 1 mm long, ovoid and

covered with erect-ascending hairs, style branches many,

laciniate-filamentous, 2-6 mm long, white to red or pink.

Fruits 2x3 mm, strongly 3-lobed, enclosed within the

enlarged (10 x 13 mm) conduplicate bracts with 5-1 1

teeth 1-5 mm long and triangular to linear; seeds 2.4-

2.6 mm long, 1.4—1.6 mm diam., oblong, surface smooth.

Plants of evergreen and partly deciduous forest

formations, 20-1300 m elevation (rarely collected

below 500 m on the Caribbean slope in Costa

Rica). Probably flowering throughout the year;

fruiting in January-July. The species ranges from

Guatemala to central Costa Rica.

Acalypha ferdinandii is recognized by the long

thick terminal 2 spikes with conspicuous toothed

bracts and the usually narrowly obovate leaves

with pinnate venation that taper to a rounded

small-auriculate base. This species is quite similar

to A. apodanthes (q.v.) with smaller leaves and

solitary 9 flowers, and it is possible that the two

are conspecific.

Acalypha hispida Burm., Fl. Ind. 203, pi. 61, f. 1.

1768.

Ornamental shrubs 1.5-3 m tall, dioecious, leafy stems

minutely hirsutulous with hairs ca. 0.3 mm long. Leaves

with petioles 2-5 cm long, ca. 1.5 mm thick, hirsutulous;

leaf blades 9-18 cm long, 5-11 cm wide, ovate, apex

usually short-acuminate, margin with 15-30 teeth/side

ca. 1 mm high, base rounded, drying thin-chartaceous,

glabrescent above, minutely puberulent on the veins be-

neath, venation palmate, 2° veins 3-5/side on the mid-

vein. Inflorescences 9 in cultivated material, 15-35 cm

long, 6-25 mm wide, pendulous, densely flowered and

reddish from the many style branches; 9 flowers with

ovary 1 x 2 mm, densely covered with minute erect

hairs, style branches 5-7 mm long; fruits and seeds usu-

ally not developing.

Acalypha hispida is planted as an ornamental

shrub because of its colorful pendant red or red-

dish purple spikes. Originally from Malaysia, it is

now grown throughout the tropics and subtropics.

In Central America it is grown at low and middle

elevations (0-2000 m). Common names are cola

degato, coladezorro, rabodegato, "chenille plant,"

"red-hot cattail," and "red cattail."

Acalypha leptopoda Mull. Arg., Linnaea 34: 39.

1865. A. lotsii J. D. Smith, Hot. Gaz. 20: 544.

1895. Figure 15.

Shrubs or small treelets, monoecious, 1-3 m tall, often

clambering or leaning over others, leafy stems 0.6-4 mm

thick, sparsely to densely pubescent with hairs 0.1-0.5

mm long, usually glabrescent and dark reddish brown;

stipules 3-15 mm long, ca. 1 mm broad at the base,

narrowed 1-2 mm above the base into a linear awn,

persisting. Leaves with petioles 3-60(-70) mm long, 0.2-

1 .3 mm thick, sparsely to densely pubescent, with minute

(0.3 mm) fimbriate glands at the adaxial apex; leaf blades

2_12(-16) cm long, l-6(-9) cm wide, ovate to ovate-

triangular or ovate-elliptic, tapering gradually to the acu-

minate apex, margins with 22-38 serrations/side ca. 1

mm high, base broadly obtuse or rounded and subcor-

date, drying thinly chartaceous, sparsely pubescent above,

more densely pubescent beneath, venation palmate, 2°

veins 4-7/side of the mid vein, strongly ascending. Male

inflorescences 2-11 cm long, 1.5-2 mm thick, peduncles

3-16 mm long, ca. 0.3 mm thick, sparsely to densely

pubescent, bracts ca. 1 mm long, pedicels 0.4-0.8 mm

long; $ flower bud ca. 0.4 mm diam., broadly ovoid,

BURGER & HUFT: FLORA COSTARICENSIS

51

perianth ca. 0.7 mm broad at anthesis. Female inflores-

cences axillary, pendant on filiform (0.1-0.2 mm) pe-

duncles 1 1-38 mm long, usually with 1 terminal bract

(rarely 2-3), bracts 1.5-3 mm long, subtending 1-3 ses-

sile flowers; 9 flowers ca. 2 mm long in early stages, ovary

0.7-1 mm long, hispidulous, styles 3-5 mm long. Fruits

verruculose, subtended by bracts 4-7 mm wide with 7-

1 1 triangular and acute or acuminate teeth 1-3 mm long;

seeds 1.6-1.9 mm long, 1.2-1.3 mm long, oblong-ellip-

soid, smooth.

Plants of evergreen lower montane forest for-

mations, (100-)500-1700 m elevation. Probably

flowering throughout the year but with most col-

lections made in June-January. The species ranges

from southern Mexico to western Panama.

Acalypha leptopoda is recognized by the slender

pendulous 2 spikes usually with only a single ter-

minal bract and one to two flowers, thin ovate

leaves with palmate venation and minute glands

at the apex of the petiole, awned stipules, and

lower montane habitats. There are sometimes more

than one inflorescence per leaf axil, but these ap-

pear to be borne on short-shoots. Different col-

lections can vary greatly in the density of pubes-

cence. This species is very similar to A. unibrac-

teata Mull. Arg. of southern Mexico and northern

Central America.

Acalypha macrostachya Jacq., Hort. Schoenbr. 2:

63, t. 245. 1797. A. seemannii Klotzsch in Seem.,

Bot. voy. Herald 102. 1853. A. pittieri Pax & K.

Hoffm., Pflanzenreich 4, 147; 16: 147. 1924. A.

hicksii Riley, Kew Bull. 1927: 126. 1927, ex

char. A. fertilis Standl. & L. O. Williams, Ceiba

1: 146. 1950, ex char. Figure 15.

Shrubs or weak-stemmed treelets l-3(-5) m tall, mo-

noecious or dioecious, leafy stems 2.5-1 1 mm thick,

densely to sparsely pubescent with hairs 0.3-1 .4(-2) mm

long, terete; stipules 5-16 mm long, 3-7 mm broad,

ovate-lanceolate and acuminate or subulate, a slender

linear tip to 10 mm long sometimes present, veins 3-5

and parallel with midrib, pubescent to glabrous. Leaves

with petioles 2.5-26 cm long, 1-3.8 mm thick, sparsely

to densely pubescent, small (0.5-0.8 mm) glands some-

times present at the apex; leaf blades (10-) 15-24 cm

long, (5.5-)8-17 cm wide, ovate to ovate-triangular, ta-

pering gradually to the acute or acuminate apex, nar-

rowed tip 6-18 mm long, margin with 30-60 teeth/side

ca. 1 mm high, base abruptly rounded and truncated

(cordate in larger leaves), drying chartaceous, with straight

hairs 0.6-1 .3 mm long on the upper surface, more dense-

ly pubescent beneath, venation palmate or subpalmate,

2° veins 5-1 I/side of midvein, 3° veins subparallel. Male

inflorescences 4-20 cm long, peduncles 3-9 mm long,

0.6-1 .5 mm thick, flowering part 2.5-5 mm thick, bracts

0.7 mm long, flower clusters closely crowded, pedicels

to 1.5 mm long; 6 flowers 0.8 mm diam. in bud, 1 mm

wide at anthesis, 0.7 mm long, sepals with straight hairs

to 0.4 mm long. Female inflorescences axillary, 9-35 cm

long, 5-14 mm wide (including styles), peduncles 1-10

mm long, 1-1.9 mm thick, usually densely pubescent,

flowers 1 /bract, up to 6 mm distant along the rachis

bracts ca. 1 mm long at anthesis and covered with whit-

ish hairs, enlarging in fruit, with 5-12 major veins and

teeth ca. 1 mm long; 9 flowers with ovary 1-1.5 mm

long, ovoid, covered with straight ascending hairs ca. 0.7

mm long, becoming enclosed within the subtending bract,

style branches exserted and 1.5-8 mm long, filiform-

laciniate and reddish. Fruits 3-5 mm wide, sessile and

enclosed within the enlarged (8x8 mm) cupulate-con-

duplicate bracts; seeds 1.9-2.2 mm long, 1.4-1.8 mm

diam., ovoid-globose, smooth, dark brown, caruncle a

whitish area ca. 0.5 mm long.

Plants often found in second growth of ever-

green wet forest and partly deciduous forest for-

mations on both the Caribbean and Pacific slopes,

10-1200 m elevation. Flowering throughout the

year (mostly January-May); fruiting February-

May. This species ranges from southern Mexico

to Bolivia and Brazil; it may be present on Cocos

Island (see below).

Acalypha macrostachya is recognized by the

generally larger leaves, long pendant inflores-

cences, the enlarged fan-like floral bracts (not pres-

ent at anthesis), and larger seeds. Most plants ap-

pear to be monoecious with several spikes of one

sex followed by several spikes of the other sex in

more distal leaf axils. Rarely, 2 spikes may have

$ flowers near the apex. The pubescence is grayish

white in life but pale yellowish in herbarium ma-

terial. Different collections can vary greatly, from

sparsely puberulent to densely villous. The sepa-

ration of such a variable species into varieties based

on pubescence serves no useful purpose (cf. Stan-

dley & Steyermark, 1949, p. 39). Two type col-

lections from Cocos Island may prove to be this

species: Pittier 16246 (photo B at F), type of A.

pittieri, and Hicks 456 (K, not seen), type of A.

hicksii. We have seen no material of this genus

from Cocos Island.

Acalypha mexicana Mull. Arg., Linnaea 34: 41.

1865. A. indica L. var. mexicana (Mull. Arg.)

Pax & K. Hoffm., Pflanzenreich 4, 147, 16: 35.

1924. Figure 11.

Herbs 1 5^*0 cm tall, branched at the base with erect

unbranched stems, leafy stems 0.3-1.8 mm thick, with

minute (0.2-0.3 mm) curved hairs along 2 longitudinal

lines; stipules 0.5-2 mm long, filiform, minutely puber-

ulent, deciduous. Leaves with petioles 6-45 mm long,

0.2-0.6 mm thick, pubescent with thin straight or curved

hairs; leaf blades 1-5 cm long, 0.8-3 cm wide, ovate to

ovate-rhombic, apex obtuse or bluntly acute, margin with

6-15 teeth/side, base rounded and obtuse to truncate,

52

FIELDIANA: BOTANY

drying membranaceous, with scattered straight hairs 0.5-

1.2 mm long on the upper surface, with shorter (0.4 m)

hairs along the veins above, venation palmate, 2° veins

2-3/side of the midvein. Inflorescences axillary, 3 spikes

1-2 cm long, slender, falling early, $ to 4 cm long with

3-6 distant bracts or 1-2 bracts crowded in the leaf axils,

sessile or short-pedunculate, sometimes with a filamen-

tous extension of the rachis and solitary distal 2 flower.

Fruits becoming 3 mm diam., subtended by an ovate to

reniform bract 3-6 mm long, 5-12 mm wide, with 9-13

rounded distal lobes 0.5-1 mm long, minutely pilose or

ciliolate along the margin; seeds 1-1.2 x 0.6-0.7 mm,

ovoid-ellipsoid with acute apex, surface smooth, grayish.

Rarely collected weeds of open sites, at 900-

2100 m elevation in Costa Rica. More common

in Mexico and Guatemala, the species is probably

an introduction in Costa Rica.

Acalypha mexicana is recognized by its short

erect unbranched stems, palmately veined leaves

with serrate margins on slender petioles, short in-

florescences at almost all nodes, and foliaceous

bracts with short rounded lobes. We have seen

only four Costa Rican specimens, from the Valle

Central, Cartago, and the lower slopes of Volcan

Irazu. This species has also been thought to be a

variety of the Asian A. indica L.

Acalypha obtusifolia Pax & K. Hoffm., Pflanzen-

reich4, 147, 16: 147. 1924.

Shrubs; stipules ca. 5 mm long, lanceolate. Leaves

with petioles 1-3.5 cm long, slender; blades 10-12 cm

long, 6-7.5 cm wide, broadly ovate, apex obtuse or short-

acute, margin denticulate, base obtuse, membranaceous,

glabrous or subglabrous, palmately 5-veined. Fruiting

inflorescence 10-1 5 cm long, short-pedunculate, sparsely

pilose, bracts 3-5 mm long, 6-7 mm wide, obovate-

truncated, with 13-15 teeth, sepal triangular, styles ca.

5 mm long; seeds 2 mm long.

This species was based on a single collection

from Punta Mala along the Pacific coast (Tonduz

6823, probably destroyed at B). We have not seen

isotypes. It was placed close to A. macrostachya

Jacq. by Pax and Hoffmann and may be an unusual

small-leaved form of that species.

Acalypha polystachya Jacq., Hort. Schoenbr. 2:

64, t. 246. 1797.

Herbs 35-90 cm tall, leafy stems 0.7-8 mm thick,

sparsely puberulent with curved hairs 0. 1-0.3 mm long,

glabrescent and terete; stipules 0.3-1 mm long or absent,

linear, caducous. Leaves with petioles l-9(-15) cm long,

0.4-1.7 mm thick, glabrous or sparsely puberulent with

curved hairs to 0.4 mm long; leaf blades 4-1 1(- 16) cm

long, 2.5-7.5(-12) cm wide, ovate to ovate-elliptic, apex

short-acuminate, rounded to the obtuse or truncate base,

teeth 20-38/side, drying membranaceous, with scattered

thin straight hairs to 1 .4 mm long on the upper surface,

glabrous to sparsely pubescent beneath, venation pal-

mate, 2° veins 2-6/side on the midvein. Male inflores-

cences 9-60 mm long, peduncles 5-20 mm long, 0.2-

0.3 mm thick, flowering portion ca. 2 mm wide, pedicels

to 0.8 mm long; <5 flower buds ca. 0.5 mm diam. Female

inflorescences terminal or in distal axils, 10-30 mm long

and 2-3 mm thick in early stages, becoming 4-12 cm

long and 1-2 cm thick in fruit, bracts usually subtending

2 sessile flowers, bracts with 7-12 narrow lobes elon-

gating in fruit; 9 flowers with ovary ca. 0.5 mm long and

styles 2 mm long in early anthesis. Fruits 2.4 mm broad,

2-3 mm long, with smooth rounded surfaces, subtended

by bracts developing elongated linear teeth to 1 1 mm

long; seeds 2.4-2.7 mm long, 1.9-2.1 mm diam., ovoid

with an acute tip (beak), surface prominently rugose.

Uncommon weedy plants of open sites in both

deciduous and evergreen vegetation, 1—400 m el-

evation. Flowering and fruiting primarily in June-

August. The few Costa Rican collections seen come

from the Pacific lowlands. The species ranges from

Mexico to Ecuador.

Acalypha polystachya is recognized by the her-

baceous habit, palmate leaves with few hairs, short

slender $ spikes, 9 spikes becoming thick with ex-

panded glabrous linear-toothed bracts, and large

fruit with somewhat rugose surface. The very small

stipules are quite unusual.

Acalypha radinostachya J. D. Smith, Hot. Gaz. 54:

243. 1912.

Shrubs, subshrubs or small treelets, 1-3 m tall, leafy

stems 2-6 mm thick, minutely (ca. 0.2 mm) appressed-

puberulent; stipules 6-13 mm long, lanceolate or subu-

late with a long narrow apex, caducous with the base

becoming thickened and pale colored, ca. 2 mm wide.

Leaves with petioles 2-23 cm long, 1-2.5 mm thick,

appressed puberulent or subglabrous, with sessile glands

0.5-1 mm wide at apex adaxially; leaf blades 1 1-26 cm

long, 6-15 cm wide, ovate to ovate-elliptic, apex acu-

minate, margin strongly serrate with 1-3 teeth/cm, base

narrowed and rounded, subcordate to truncate, drying

thinly chartaceous and dark green, subglabrous or mi-

nutely puberulent beneath at maturity, venation pal-

mate, 2° veins 3-5/side of the midvein. Male inflores-

cences axillary to distal leaves, solitary, 8-22 cm long,

spicate, peduncles ca. 1.3 mm thick, flowering portion

ca. 2 mm thick, minutely puberulent, bracts 0.5 mm

long, difficult to see, glomerules with 3-6 flowers; <5 flower

buds ca. 0.4 mm diam., globose. Female inflorescences

terminal, solitary, 23—45 cm long, spicate, peduncles 2-

2.5 mm thick, densely or sparsely puberulent, bracts 2-

3 mm long, becoming 4 mm wide, with 2-3 lobes 0.5-

1 .2 mm high, green but drying dark, bracts closely clus-

tered or separate; 2 flower 1 /bract, ovary ca. 2 mm long,

2-3 mm wide, broadly ovoid, glabrous, styles 3-6 mm

long, laciniate. Fruits ca. 2-2.5 mm long, ca. 3 mm wide,

sessile, subtended by bracts not exceeding 3 mm in length,

to 5 mm wide.

BURGER & HUFT: FLORA COSTARICENSIS

53

Plants of the wet evergreen Caribbean slope,

100-300 m elevation. Flowering February and

May-September. The species is known only from

La Selva and the Llanuras de Santa Clara (/. D.

Smith 6849 us the type) in north-central Costa

Rica.

Acalypha radinostachya is recognized by its long

terminal (apparently erect) 2 inflorescences, 2 bracts

that do not become significantly enlarged, larger

ovate leaves with large blunt teeth, and the thick

hard whitish base where the stipules were at-

tached. The 2 inflorescences are described as green,

with style branches sometimes becoming white.

Acalypha macrostachya is vegetatively similar but

the blades are broadly rounded at the base, and

the stipule scars do not become hard and smooth.

Also, A. radinostachya is never densely villose as

are some collections of A. macrostachya.

Acalypha schiedeana Schldl . . Linnaea 7: 304. 1 832.

Figure 14.

Shrubs 1-3 m tall, much branched, leafy stems, 1.3-

5 mm thick, glabrous or with thin whitish hairs 0.2-0.4

mm long; stipules 7-10 mm long, 0.7-1.2 mm broad at

the base, filiform (ca. 0.2 mm thick) above the short (ca.

1 mm) base. Leaves with petioles 2-7 cm long, 1.1-1.5

mm thick, glabrous or pubescent, usually with small (0.2

mm) digitate glands at the apex; leaf blades 6-18 cm

long, 4-1 1 cm wide, ovate to elliptic-ovate, apex usually

short-acuminate, margin with 12-35 teeth/side, base

rounded and truncate or subcordate, drying membra-

naceous, with thin hairs 0.3-0.8 mm long on veins above

and below, venation palmate, 2° veins 3-4/side along

the midvein. Male inflorescences 1-13 cm long, ca. 1.5

mm wide, peduncles 2-14 mm long, ca. 0.6 mm thick,

pubescent, pedicels ca. 0.5 mm long; <3 flower with peri-

anth ca. 0.4-0.5 mm wide, anther-clusters 0.4-0.5 mm

wide. Female inflorescences terminal, 4-18 cm long, be-

coming 6-1 4 mm thick in fruit, peduncles 6-14 mm long,

0.7-0.9 mm thick, pubescent, flowers at first with minute

bracts and separate along the rachis, sessile, becoming

congested; 9 flowers with ovary 0.5-1.5 mm long, mi-

nutely hispidulous, styles 1.5-3 mm long, laciniate dis-

tally. Fruits ca. 3 mm broad, smooth, solitary within

conspicuous bracts 3-12 mm long, with 7-13 lobes 1-2

mm long, triangular to lanceolate, bracts usually with

thin hairs 0.4-1.5 mm long; seeds 1.7-2 mm long, 1.3-

1 .5 mm diam., ovoid, grayish, caruncle not elevated, 0.7

mm long.

Uncommon plants of moist evergreen sites in

deciduous forest formations on the Pacific slope,

0-800 m elevation in Costa Rica. Flowering in

late May-early June; fruiting in June (June-De-

cember in northern Central America). This species

is known in Costa Rica from Sta. Rosa N.P., ri-

parian forest near Bagaces and Canas, and San

Luis (below Monteverde). The species ranges from

central Mexico to northern Puntarenas Province,

Costa Rica.

Acalypha schiedeana is recognized by the shrub-

by habit, ovate leaves with palmate venation, nar-

row stipules, conspicuous terminal 2 spikes, and

broad bracts with relatively short teeth subtending

the fruit.

Acalypha septemloba Mull. Arg., Flora 55: 27.

1872. Ricinocarpus irazuensis O. Ktze., Rev.

gen. pi. 2: 616. 1891. A. irazuensis (O. Ktze.)

Pax & Hoftm., Pflanzenreich 85 (IV, 147, XVI):

53. 1924. Figure 14.

Herbs or subshrubs, to 1 m tall, leafy stems 0.3-2 mm

thick, with thin curved whitish hairs 0.2-0.4 mm long;

stipules 0.5-1.5 mm long, triangular to subulate, cadu-

cous. Leaves with petioles 4—40 mm long, 0.3-0.6 mm

thick, pubescent with thin whitish hairs, with minute

digitate glands at the apex or adjacent to a gland-like

area on the blade; leaf blades 1-7 cm long, 1-4 cm wide,

ovate to ovate-triangular (suborbicular in very small

leaves), apex acute or subacuminate, margin with 1 2-22

teeth/side, base rounded and obtuse or truncate, drying

membranaceous, with scattered appressed straight hairs

0.2-0.9 mm above, with shorter hairs beneath, venation

palmate or subpalmate, 2° veins 2-3/side on the mid-

vein. Male inflorescences 0.8-2 cm long, 1.5 mm wide,

bracts ca. 0.6 mm long, peduncles ca. 3 mm long, ped-

icels 0.5 mm long; <3 flower buds ca. 0.4 mm diam. (the

mostly <? inflorescences often bisexual with 1-2 $ flowers

at apex or base). Female inflorescences terminal, 2-9 cm

long and 7 mm wide, enlarging in fruit to 10 mm wide,

peduncles 0—4 mm long; 2 flowers 1 /bract, sepals 0.5-

0.8 mm long, ovary ca. 0.6 mm long, style branches 2-

4 mm long, reddish. Fruits ca. 2.6 mm diam., subtended

by bracts 3-5 mm long, to 6 mm wide, with short (1-2

mm) triangular or digitate lobes; seeds ca. 1.3 x 0.8 mm,

ovoid-ellipsoid, smooth.

Uncommon plants of evergreen montane for-

mations, 1100-1900 m elevation. Flowering in

July-January; fruiting in November-December.

The species ranges from central Costa Rica to

western Panama.

Acalypha septemloba is recognized by its higher-

elevation habitat, short weak-stemmed habit, very

small stipules, glandular processes at the junction

of petiole and blade, and floral bracts with short

acute or rounded lobes. The reddish style branches

are conspicuous at anthesis.

Acalypha setosa A. Rich, in Sagra. Hist. fis. Cuba

Dot. T. XI: 204. 1850.

Herbs 0.3-0.8 m tall, usually with a single main stem

and few lateral branches, leafy stems 0.8-4 mm thick,

with thin curved hairs ca. 0.2 mm long; stipules 1-2 mm

long, 0. 1-0.2 mm wide, persisting or deciduous. Leaves

54

FIELDIANA: BOTANY

with petioles 1-7 cm long, 0.3-0.8 mm thick, with thin

curved ascending hairs; leaf blades 2.5-10 cm long, 1.5-

6.5 cm wide, broadly ovate to ovate-triangular, abruptly

short-acuminate at the apex (acute), marginal teeth 5-

8/cm, base broadly obtuse to truncated, drying mem-

branaceous, with straight appressed hairs 0.4-0.8 mm

long on the upper surface or glabrescent, lower surface

with inconspicuous hairs along the major veins, venation

palmate, midvein with 2° veins 2-4/side. Male inflores-

cences at distal nodes, solitary, 8-25 mm long, flowering

portion 1.5-2 mm diam., rachis 0.2-0.3 mm thick, fil-

aments 0.2-0.4 mm long; $ flowers ca. 0.4 mm wide at

anthesis. Female inflorescences axillary to distal nodes

or appearing terminal (abnormal $ inflorescences often

at lower nodes), 3-12 cm long, flowering portion 3-1 1

mm wide, bracts 2-7 mm long, with 9-13 narrow lobes

up to 6 mm long, enclosing 1 9 flower; ovary pubescent,

styles not conspicuous. Fruits 1.5-2 mm long, 2-3 mm

wide, 3-lobed, with few erect hairs; seeds 1.2-1.4 mm

long, 1-1.2 mm wide, subglobose to ovoid, smooth.

Weedy plants of open or disturbed sites in de-

ciduous and evergreen areas, 5-900 m elevation

(in northern Central America). Flowering and

fruiting throughout the year in northern Central

America. The species ranges from Mexico to

northern Costa Rica and from the West Indies to

northern South America.

Acalypha setosa is recognized by its short her-

baceous habit, broadly ovate leaves with truncated

base and palmate venation, and the 9 bracts with

long narrow lobes. The small linear stipules and

very short 6 spikes are also characteristic. This

species may be mistaken for A. polystachya, but

the seeds of the two species are very different. This

species has only recently been collected in Guan-

acaste Province (Wilbur et al. 23031 & 31203

DUKE) and may be a recent introduction.

Acalypha triloba Mull. Arg., Linnaea 34: 23. 1 865.

Herbs to ca. 1 m tall, leafy stems 1-4 mm thick, hirsute

with thin straight somewhat retrorse hairs 1-2 mm long,

shorter (0.1-0.3 mm) hairs also present; stipules 1.5-5

mm long (or absent), linear to narrowly triangular. Leaves

with petioles 2-7 cm long, 0.5-0.8 mm thick, with thin

straight hairs 0.3-2 mm long; leaf blades 4—10 cm long,

2-6 cm wide, ovate-elliptic to ovate or ovate-triangular,

apex acuminate, margin serrate with ca. 5 teeth/cm (Cos-

ta Rica) or 2-3 teeth/cm (Mexico and Guatemala), base

obtuse to rounded and truncate, drying chartaceous, sur-

faces with thin straight hairs 0.5-1.5 mm long, venation

palmate, 2° veins 4-5/side of midvein and strongly as-

cending. Male inflorescences solitary, 5-12 cm long, pe-

duncles 8-60 mm long, flowering portion 1.5-2.5 mm

thick, flower buds 0.3-0.5 mm diam., pedicels less than

1 mm long; <5 flowers with anthers 0.2-0.3 mm wide.

Female inflorescences terminal or axillary to distal leaves,

solitary, 3-7 cm long, 3-12 mm wide (including styles),

rachis densely pubescent, flowers 2-3/bract (original de-

scription) or apparently 1 /bract (Costa Rican collection),

sessile, bracts with 3 distal lobes; $ flowers with calyx

ca. 1 mm long, ovary densely pubescent, styles 4-6 mm

long, laciniate, becoming reddish. Fruits and fruiting in-

florescences not seen; seed foveolate-puncticulate (orig-

inal description).

Acalypha triloba is a poorly known species of

Mexico and Guatemala with a single Costa Rican

collection placed here provisionally. The species

is unusual because of its $ spikes with long thin

peduncles, long slender petioles, and the stems and

leaves with straight slender hairs to 2 mm long. A

Guatemalan collection (Steyermark 51959 F) was

collected at 2500 m elevation, but the Costa Rican

collection came from a partly shaded roadside at

ca. 100 m elevation near Bahia El Coco in Guan-

acaste Province in late July (Burger & Burger 7753,

distributed as A. polystachya?). The Costa Rican

collection differs in having more finely serrate

leaves and less well-developed stipules, and the 2

flowers appear to be solitary on the young spike.

We thank Geoffrey Levin for the provisional de-

termination of this collection.

Acalypha villosa Jacq., Enum. Syst. PI. 32, 1760;

Sel. Stirp, PI. Amer. 254, t. 183, f. 61. 1763.

Figure 15.

Weak-stemmed shrubs or small treelets 0.5-3(-8) m

tall, usually monoecious, leafy stems 1.3-5 mm thick,

sparsely to densely pubescent with minute (0. 1 mm) or

villose yellowish hairs 0.3-0.9 mm long; stipules 2-10

mm long, narrowly triangular to lanceolate, acuminate,

often with a distinct midvein and thin lateral margins.

Leaves with petioles 2.5-14 cm long, 0.6-2 mm thick,

sparsely to densely pubescent, often with elevated or

lanceolate glands 0. 5- 1 . 5 mm long at the apex and drying

dark; leaf blades 8-17(-25) cm long, 5-ll(-13.5) cm

wide, ovate to ovate-triangular, tapering gradually to the

acute or acuminate apex, margin crenate-serrate with

25-75 teeth/side 0.5-2 mm high, usually abruptly round-

ed to the truncated or cordate base, drying thin-char-

taceous, sparsely strigose to glabrate above, more densely

pubescent below with hairs 0.3-0.9 mm long (rarely gla-

brous), venation palmate or subpalmate, 2° veins 4-7/

side of the midvein, 3° veins subparallel; minute pellucid

dots sometimes present on the lower surface. Inflores-

cences almost always unisexual and unbranched, usually

axillary, often with a series of axils bearing the same sex

followed by a number of axils bearing the other sex,

puberulent. Male inflorescences 4-12 cm long, 1.8-3.6

mm diam., spicate, peduncles 4-12 mm long, 0.3-1 mm

thick, flower clusters sessile and closely congested, ob-

scuring the rachis until after anthesis, bracts 0.7-1 mm

long, broadly triangular, often ciliolate, pedicels 0.5-1.5

mm long; <5 flowers ca. 1 mm wide, sepals ca. 0.5 mm

long, with a glabrous perianth-like inner whorl drying

and brownish (ca. 0.4 mm long), anthers ca. 0.1 mm

long. Female inflorescences becoming racemose, 5-16

cm long, peduncles 5-25 mm long, rachis 0.2-0.3 mm

thick, flowers mostly solitary, subtended by minute (0.5

BURGER & HUFT: FLORA COSTARICENSIS

55

mm) bract and tufted hairs, pedicels 1-2 mm long, to 4

mm in fruit; 2 flowers with sepals ca. 0.5 mm long,

persisting in fruit; ovary 0.8-1.3 mm long, style column

0.3 mm long, style branches 1-2 mm long, often drying

yellowish (red in life). Fruits 1.5 x 2 mm, prominently

3-lobed, muricate with narrow projections 0.1-0.3 mm

long, persisting columella ca. 0.7 mm long, expanded

apically; seeds 0.8-1.4 mm long, 0.7-1.3 mm diam.,

ovoid or subglobose, smooth, pale brown.

Plants of evergreen forest formations on both

Caribbean and Pacific coasts, 1-800 m elevation.

Probably flowering and fruiting throughout the year

in Central America. The species ranges from Mex-

ico to Brazil and Paraguay.

Acalypha villosa is recognized by the slender 2

racemes with small isolated flowers and the base

of the leaf blades consistently broad and rounded

to a truncated or cordate base. Occasional collec-

tions with near-terminal 2 inflorescences with many

slender lateral branches occur in Honduras and

Nicaragua (rarely in Costa Rica) and can be easily

confused with A. costaricensis. This species is less

common in Costa Rica than the closely related A.

costaricensis (q.v.).

Acalypha sp. aff. A. mortoniana Lundell, Bull.

Torrey Bot. Club 64: 552. 1937.

Shrubs ca. 3.5 m tall, leafy stems 1.2-4 mm thick,

densely puberulent with short (0.2-0.3 mm) curved as-

cending or appressed hairs; stipules 3-4 mm long, linear

or setaceous. Leaves with petioles 3-13 cm long, 0.8-

1 .8 mm thick, densely minutely puberulent, apical glands

absent; leaf blades 12-18 cm long, 5-8 cm wide, elliptic

to elliptic-oblong or narrowly ovate-elliptic, apex acu-

minate, margin with short (0.5 mm) gland-tipped teeth,

base cuneate to obtuse, drying membranaceous or thin-

chartaceous, dark, minutely puberulent on the veins

above, sparsely puberulent beneath, venation palmate

or subpalmate, midvein with 4-5 2° veins/side. Male

inflorescences 6-12 cm long, 3-4 mm thick (with flow-

ers), rachis 0.2-0.3 mm thick, puberulent, bracts ca. 1

mm long, subtending 3-7 flowers, pedicels ca. 1 mm

long; 3 flowers ca. 1 mm wide. Female inflorescences

terminal, to 14 cm long in fruit, not seen at an thesis,

fruiting bracts 5-6 mm long, broadly conduplicate-ren-

iform, apically emarginate or with a short sinus, margin

entire and with prominent gland-tipped hairs 0.5-1.5

mm long, surfaces with few thin hairs, each bract sub-

tending a solitary fruit. Fruits 5-6 mm long, ca. 6 mm

wide, subglobose, sessile, partly enclosed by the bract;

seeds 3.7—4.2 mm long, ca. 3 mm diam., ovoid-ellipsoid,

smooth, brown.

Known only from primary evergreen forest at

Estacion Cacao (10°55'38"N,85°29'38"W) at 1100

m elevation. Flowering and fruiting in June. This

taxon is represented by a single collection (Delgado

29) from northwestern Costa Rica.

Acalypha sp. aff. A. mortoniana is recognized

by its larger elliptic leaves on long petioles, slender

$ spikes, and prominent erect fruiting spikes with

floral bracts bearing gland-tipped hairs along their

rounded entire margins. Our collection is very

similar to material of A. mortoniana from Gua-

temala and may prove to be a southern subspecies.

The following key highlights the differences be-

tween our collection and the Guatemalan material.

la. Leaf blades mostly elliptic and narrowed gradually to the base, serrations small or obscure; fruiting

bracts often emarginate at the apex (Delgado 29)

Ib. Leaf blades mostly ovate and rounded at the base, usually with prominent (0.5-1.5 mm high)

serrations; fruiting bracts often with a single apical tooth A. mortoniana

Acidoton Swart/

Shrubs or small treelets, dioecious, stinging hairs

sometimes present, spines absent; stipules paired at the

leaf base, small, deciduous or persistent. Leaves alter-

nate, simple, petiolate, without glands or stipels; leaf

blades entire to crenate or dentate, pinnately veined,

domatia often present. Inflorescences axillary, racemose

with flowers in fascicles along the length of the single

rachis, bracts eglandular, 6 flowers subsessile or pedi-

cellate, 9 flowers pedicellate. Male flowers with 3-5 se-

pals, valvate in bud, petals absent, disk absent or part

of the raised receptacle; stamens ca. 22-60, filaments

free, slender, glabrous, anthers dehiscing longitudinally,

extrorse, connective with a minute tuft of stinging hairs

at its apex; pistillode absent. Female flowers with 5-6

sepals, narrow and imbricate, petals and disk absent;

ovary 3-locular, covered with stiff stinging hairs, ovules

1/locule, styles with basal column and 3 papillate

branches. Fruits capsular, deeply 3-lobed and breaking

into 3 2-valved cocci, surfaces with stinging hairs; seeds

rounded, ecarunculate.

A small genus of approximately six species cen-

tered in the Caribbean. It is related to Tragia but

differs in having the connective terminated by

stinging hairs. One species is found in Central

America.

Acidoton nicaraguensis (Hemsl.) G. Webster, Ann.

Missouri Bot. Gard. 54: 191. 1967. Cleidion ni-

caraguense Hemsl., Biol. centr. amer. Bot. 3:

56

FIELDIANA: BOTANY

130. 1883. Gitara panamensis Croizat, J. Ar-

nold Arbor. 26: 192. 1945. Figure 12.

Shrubs or small treelets l-5(-7) m tall, dioecious, leafy

stems 0.9-4 mm thick, with thin whitish hairs, glabres-

cent and gray in age, epidermis exfoliating in longitudinal

strips on older stems; stipules 1.5-6 mm long, 0.8-1.8

mm broad at base, triangular to lanceolate, glabrous or

puberulent abaxially, persisting and brown, veins par-

allel and prominent or obscure. Leaves with petioles 2-

6 mm long, ca. 1 mm thick, densely strigose with stiff

ascending or erect hairs 0.2-0.6 mm long; leaf blades 8-

2 1 cm long, 3-7 cm broad, narrowly elliptic-oblong, nar-

rowly ovate-elliptic or elliptic, apex acuminate with a

narrowed tip 7-25 mm long, margin distally crenate-

dentate with gland-tipped teeth 0-4 mm long, base grad-

ually narrowed and cuneate, slightly rounded at the pet-

iole, drying chartaceous and dark green to greenish gray

or brown, glabrous or minutely puberulent on the veins

above, glabrous beneath but with some hairs along the

veins and in the vein axils (domatia), with 4-7 major

secondary veins on each side. Inflorescences 1-3 on ax-

illary short-shoots, unisexual, axillary or pseudotermin-

al, $ 0.5-5 cm long, 9 ca. 1 cm long but elongating in

fruit, racemose, subtended at the base by a series of

imbricate stipules, peduncles 3-8 mm long, 0.3-0.4 mm

thick, <5 flowers in alternate fascicles of 2-4, 9 flowers 2-

4 and alternate along the strigulose unbranched or few-

branched rachis, bracts to 2 mm long, acute, <3 pedicels

to 3 mm long, 9 pedicels ca. 1 mm long. Male flowers

white or yellowish, sepals 3, 1.5-3 mm long, 0.8 mm

broad at the base, pubescent on the exterior, stamens ca.

21, filaments 1.3-2.5 mm long, 0.1-0.2 mm thick, erect,

drying orange-brown, anthers 0.2-0.4 mm long, 0.2-0.3

mm broad, connective apex with a minute (0. 1 mm) tuft

of stinging hairs (difficult to see). Female flowers white

or yellowish, sepals 1.3-2 mm long, 0.5-0.8 mm broad,

narrowly acute; ovary 1-1.7 mm long, covered with stiff

ascending hairs, style column 0.4-1.2 mm long, style

branches 1.3-2.7 mm long, recurved, papillose. Fruits

5-6 mm long, 8-10 mm broad, deeply 3-lobed and

breaking into cocci 4-5 mm broad, surfaces with sharp

stinging hairs; seeds 4—4.5 mm long, subglobose.

Plants of evergreen forest formations on both

the Pacific and Caribbean slopes, 0-700 m ele-

vation (to 1000 m in Nicaragua). Flowering in

January-July; fruiting in March-October. While

the species is not often collected in Costa Rica, it

can be locally common (as at Volcan Orosi). The

species ranges from Guatemala to Peru.

Acidoton nicaraguensis is recognized by the nar-

row short-petiolate leaves with prominent gland-

tipped teeth, domatia in vein axils, slender axillary

spicate/racemose inflorescences, $ flowers with

many closely congested filaments, minute anthers,

and fruits with rounded cocci and stinging hairs.

This species appears to be common in eastern Nic-

aragua; it has been called mala in southeastern

Honduras, perhaps because of the stinging hairs,

which may be present on the foliage as well as on

the flowering parts. The South American A. \e-

nezolanus (Croizat) Webster may be conspecific.

Actinostemon Martius ex Klotzsch

REFERENCE— E. Jablonski, Notes on Neotropi-

cal Euphorbiaceae 4. Monograph of the genus Ac-

tinostemon. Phytologia 18: 213-240. 1969.

Trees and shrubs, monoecious, stems glabrous or pu-

berulent, inflorescence buds enclosed in a tight series of

imbricate stipule-like bud-scales; stipules lateral. Leaves

alternate, simple, usually short-petiolate, often coria-

ceous or subcoriaceous, usually glabrous, margins entire,

venation pinnate. Inflorescences terminal or axillary,

solitary or 2-3/node, bisexual or unisexual, racemes with

an unbranched rachis, at first subtended by imbricate

deciduous bracts; <5 flowers usually 2-3/bract, each flower

borne on a thin pedicel; 9 flowers 1 (2-3) and proximal

on the rachis, borne on long pedicels. Male flowers mi-

nute, calyx and corolla absent, disk absent; stamens 2-

1 6 or many, filaments free, anthers erect, ovoid, dehisc-

ing longitudinally; pistillode absent. Female flowers small,

calyx absent or represented by 1-3 minute lobes, corolla

and disk absent, staminodes absent; ovary 3-locular,

smooth or tuberculate, ovules 1/locule, styles united for

a short or longer length, free and recurved distally, simple

(undivided). Fruits capsules, glabrous to sericeous,

breaking into 3 2-valved cocci, columella persisting; seeds

subglobose, carunculate, endosperm fleshy, cotyledons

plane and flat.

A Neotropical genus of 1 3 species; most species

are found in southeastern South America, with

outliers in Cuba, the Lesser Antilles, Venezuela,

and the Amazon basin. The strobilus-like inflo-

rescences are at first enclosed in a tight series of

imbricate bracts. This, in addition to the virtually

naked flowers and restriction to dry deciduous

lowlands in Costa Rica, help distinguish our rep-

resentative of this genus. In appears that the pro-

tection of the young floral organs by the bud-scale-

like bracts compensates for the loss of a protective

perianth. Webster (1 994b and earlier) includes this

genus in Gymnanthes.

Actinostemon caribaeus Griseb., Abh. Ges. Wiss.

Gottingen 7: 168. 1857. Excoecaria caribaea

Griseb., Fl. Brit. W. Ind. 51. 1864. A. concolor

var. caribaeus (Griseb.) Mull. Arg. in DC., Prodr.

15(2): 1193. 1868. Figure 25.

Small trees or shrubs 2-5 m tall, to ca. 10 cm trunk

diam., leafy stems 1.4—4 mm thick, glabrous, longitu-

dinally striate; stipules ca. 3 mm long, glabrous, quickly

caducous and leaving small scars, shoot-apices covered

by stipule-like glabrous bud-scales (3-7 mm long) that

dry dark reddish brown and leave a circle around the

BURGER & HUFT: FLORA COSTARICENSIS

57

stem when they fall. Leaves glabrous, petioles 3-7 mm

long, 0.5-2 mm thick, drying brown; leaf blades 5-1 1

cm long, 1.8-4.7 cm wide, elliptic-obovate to narrowly

obovate or narrowly elliptic-oblong, apex obtuse to acute,

often with a small (0.3 mm) glandular tip, margin entire

and drying slightly revolute, tapering gradually to the

cuneate base, slightly (0-3 mm) lobed or auriculate at

the petiole, drying subcoriaceous and grayish, 2° veins

8- 11 /side and loop-connected distally, with usually 4

dark flat glands (0.3-0.4 mm diam.) near the base be-

neath. Inflorescences axillary or pseudoaxillary, solitary,

bisexual or <5, 1.5-4 cm long, with a single unbranched

racemose axis, peduncle 1-5 mm long, with a solitary

proximal 2 flower subtended by stipule-like bracts, distal

rachis 0.3-0.7 mm thick and winged, yellowish, 6 flowers

subtended by linear bracts 2-4 mm long. Male flowers

lacking perianth (naked), borne on a pedicel 0.5-3 mm

long, with 2-5 slender filaments 0.3-0.8 mm long, an-

thers 0.3-0.5 mm long. Female flowers glabrous, lacking

perianth, pedicel 1-15 mm long and continuous with the

ovary base, ovary ca. 2 mm long, 0.8 mm diam., style

base 2-4 mm long (to 5 mm in fruit), style branches 3-

5 mm long, papillose adaxially. Fruits 10-12 mm long,

9-12 mm diam., greenish in life, borne on pedicels 1-5

cm long, outer wall of cocci 0.5 mm thick, columella 7

mm long, 4 mm wide at apex; seeds ca. 6.8 x 4.5 x 3.5

mm, oblong, caruncle 1 mm high.

Plants of deciduous lowland and adjacent partly

deciduous forests, 100-700 m elevation (to 1000

m in Nicaragua). Flowering in June (Hammel

17777 CR, Zamora et al. 1255 CR, F); fruiting in

August (Q. Jimenez et al. 868 CR) and September

(Q. Jimenez 385 F). This species has only recently

been collected in northern Guanacaste Province,

Costa Rica, and central Nicaragua; this species

also occurs in the Lesser Antilles and northern

Venezuela.

Actinostemon caribaeus is recognized by its lack

of pubescence, often narrowly obovate leaf blades

with glandular punctations in the lower lamina

base, slender little inflorescences with stalked 9

flowers and clustered $ flowers, and flowers lacking

calyx or corolla (naked). The 9 flower exhibits al-

most no differentiation between pedicel and ovary

base or ovary apex and stylar column. Thus, the

$ flowers appear as stipitate pistils. The narrowly

ovoid apical buds with overlapping scales and acute

apex are also distinctive. This species is closely

related to A. brachypodus (Griseb.) Urban of Cuba

and A concolor (Spreng.) Mull. Arg. of southeast-

ern Brazil and Paraguay.

Adelia Linnaeus

Shrubs or small trees, dioecious, branchlets often with

spines (leafless short-shoots), pubescence simple, gla-

brescent; stipules small and paired at the leaf base. Leaves

alternate, simple, petiolate; leaf blades pinnately veined,

margins entire, membranaceous to chartaceous, with tufts

of hairs (domatia) in the vein axils beneath and along

some of the major veins, pellucid-punctate. Inflores-

cences axillary, unisexual, $ flowers fasciculate on re-

duced short-shoots, small, pedicels slender and short to

long, often articulate in the middle; 2 flowers paired in

the axils and long-pedicellate. Male flowers with calyx

of 4-5 parts, valvate in bud, petals absent, disk extra-

staminal and annular (rarely of 5 glands), adnate to the

calyx; stamens 6-30, filaments free or becoming connate

basally, slender, anthers versatile, dorsifixed, with par-

allel divergent thecae, dehiscing longitudinally, a small

pistil lode sometimes present at the apex of the staminal

column (Croat, 1978). Female flowers with 5-7 narrow

sepals, reflexed at anthesis, petals and staminodes ab-

sent, disk annular and pubescent; ovary usually 3-lobed

and 3-locular, styles 3, free, laciniate, ovules 1/locule.

Fruits capsular, 3-lobed, puberulent, usually separating

into 3 2-valved cocci with loculicidal dehiscence; seeds

mostly carunculate.

A genus of 10-12 Neotropical species, best rep-

resented in the West Indies.

Adelia triloba (Mull. Arg.) Hemsl., Biol. centr.

amer. Bot. 3: 130. 1883. Ricinella triloba Mull.

Arg., Linnaea 34: 153. 1866. Figure 31.

Shrubs or small trees, 3-15 m tall, trunk 12-20(-30)

cm thick, leafy stems 1-3.5 m thick, minutely (0.1 mm)

puberulent or glabrous, yellowish to pale gray, with small

(0.3 mm) rounded lenticels, straight spines 8-22 mm

long sometimes present, 1-2 mm thick at the base; stip-

ules 0.5-3.5 mm long, triangular to linear-subulate, gla-

brous and lustrous on the exterior, deciduous. Leaves

with petioles 3-7(-9) mm long, 0.4-1.5 mm thick, mi-

nutely puberulent or glabrous, glands absent; leaf blades

8-17(-23) cm long, 2.5-7(-9) cm broad, elliptic to ellip-

tic-oblong or narrowly obovate, apex acuminate, grad-

ually narrowed to the cuneate base, often slightly round-

ed at the petiole, drying chartaceous and greenish or

grayish, glabrous and the major veins prominent above

(dry), with whitish hairs 0.2-0.4 mm long usually along

major veins beneath, 2° veins 3-6/side, vein axils often

lined by hairs (domatia) beneath. Male flowers in fas-

cicles of up to 50 flowers, bracts to 2 mm long, pubescent

at the base, pedicels 3-10 mm long, slender, minutely

puberulent, flower buds ca. 2 mm diam., globose; sepals

4-5, 2-2.5 mm long, pale yellowish; stamens 6-30, sta-

minal column short or not apparent, filaments 0.5-1.8

mm long, filiform, anthers 0.4 mm long, 0.5-0.6 mm

broad. Female flowers pendulous on slender pedicels 1-

3 cm long (to 7.5 cm in fruit), 0.3-0.5 mm thick, glabrous

or minutely puberulent, sepals 4-6, 3-6 mm long, 0.5-

1 mm broad; ovary ca. 2 mm long, 2.5-3 mm wide,

3-lobed, densely puberulent with erect hairs 0. 1-0.2 mm

long, styles 1.5-3 mm long, laciniate distally. Fruits 6-

9 mm long, 8-12 mm wide, oblate and slightly to deeply

3-lobed distally, pubescent, pendulous on the slender

pedicels, splitting from the top, persisting columella 3-

4.2 mm long, 0.7 mm thick, expanded at apex; seeds

3.8-5 mm long, subglobose, with or without a mottled

color surface, smooth, with a linear longitudinal raphe.

58

FIELDIANA: BOTANY

Plants of evergreen and partly deciduous forest

formations of both the Pacific and Caribbean

slopes, 10-1000 m elevation. Flowering in De-

cember-February; fruiting in January-April. The

species ranges from southern Nicaragua to eastern

Panama.

Adelia triloba is recognized by the spiny stems

(when present), fruits pendulous on long slender

pedicels, persisting columella, the fasciculate $

flowers, leaves with pubescent little domatia, and

restricted flowering/fruiting period. In addition,

the leaves are short-petiolate and pellucid-punc-

tate. Some collections have distinctively long ( 1 5-

20 cm) narrow (ca. 6 cm) leaf blades. The plants

are called espino de playa in Nicaragua. This spe-

cies is closely related to Adelia barbinervis Schldl.

& Cham. (Mexico to Nicaragua), but that species

lives in seasonally dry deciduous and open sec-

ondary forests and has smaller leaves than A. tri-

loba, and the fruits are not deeply lobed.

Adenophaedra (Miiller Argoviensis)

Muller Argoviensis

Shrubs or small trees, dioecious, hairs simple, sap not

milky; stipules paired at the leaf base. Leaves alternate,

simple, petiolate, pinnately veined, entire or dentate with

gland-tipped vein endings, with laminar glands. Inflo-

rescences axillary or terminal, 1-3/node, spiciform, bracts

without glands, subtending 1 9 flower or several closely

congested $ flowers, flowers pedicellate. Male flowers

globose in bud, sepals 3, valvate in bud, petals absent,

disk absent; stamens 2-3, alternate with sepals, filaments

very short, anthers ovate, dehiscing longitudinally and

introrse, connective enlarged distally; pistillode absent

or minute. Female flowers with 6 sepals in 2 series, in-

terior whorl smaller, imbricate in bud, petals absent,

staminodes absent, disk annular and 3-lobed; ovary

3-lobed, 3-locular, style short or minute with broad ses-

sile stigmas, ovules 1/locule. Fruits capsular, promi-

nently 3-lobed, depressed at the apex, separating into 3

2-valved cocci; seeds globose, ecarunculate, surfaces

smooth.

A genus of three South American species with

one reaching central Costa Rica. The pendulous

unisexual spike-like inflorescences, minute $ flow-

ers with few subsessile stamens, and 9 flowers with

six imbricate sepals and broad sessile stigmas help

distinguish the genus.

Adenophaedra grandifolia (Klotzch) Mull. Arg. in

Mart., Fl. Bras. 11 (2): 386. 1874. Tragia gran-

difolia Klotzsch, London J. Hot. 2: 46. 1843.

Bernardia grandifolia (Klotzsch) Mull. Arg.,

Linnaea 34: 173. 1865. Cleidion denticulatum

Standl., Publ. Field Columb. Mus., Bot. Ser. 4:

2 1 8. 1 929. Bernardia denticulata (Standl.) Web-

ster, Ann. Missouri Bot. Gard. 54: 200. 1967.

Figure 13.

Shrubs or small trees, 2-6(-8) m tall, leafy stems 1-6

mm thick, with stiff ascending hairs 0.2-0.5 mm long,

glabrescent, becoming dark reddish brown; stipules 3-

13 mm long, 1-2 mm wide at the base, oblong to nar-

rowly lanceolate, densely strigose to glabrous, deciduous.

Leaves with petioles 5-18 mm long, 1.3-2.3 mm thick,

strigose and glabrescent; leaf blades ( 1 0-) 1 8-33 cm long,

(2-)5-13 cm wide, narrowly obovate-oblong to oblan-

ceolate or elliptic-oblong, apex short-acuminate or cau-

date-acuminate, narrowed tip 4-14 mm long, margins

dentate with 1 9-28 teeth/side (entire along basal third),

teeth 0.5-1 mm high, tapering gradually to a cuneate

base with the margin sometimes thickened near the base,

flat rounded imbedded glands often present near the lam-

ina base adaxially, drying stiffly chartaceous to subcor-

iaceous, with thin whitish hairs ca. 0.5 mm long on the

upper surface and glabrescent, with hairs 0.2-0.5 mm

long beneath, 2° veins 7- 11 /side. Male inflorescences

axillary, 1-3, $ to 26 cm long with up to 60 glomerules

separated by 4—12 mm and with 2-6 flowers/glomerule,

fallen flowers leaving stiff persistent pedicels to 1 mm

long; $ flower buds ca. 0.7 mm diam., 0.5 mm long,

sepals 0.8 mm long, 0.6 mm broad at the base, with

sharp straight hairs on the outer surface, glabrous within;

stamens 3, subsessile, anthers 0.2 mm broad. Female

inflorescences to 12 cm long with 4-7 flowers, rachis

densely hirsute or strigose with stiff whitish hairs 0.2-

0.4 mm, bracts 1-1.5 mm long; 2 flowers with perianth

parts ca. 2.2 mm long, 2 mm wide at the base, outer

surface with stiff ascending hairs, stigmas ca. 0.5 mm

long and equally broad. Fruits 6-9 mm long, 13-18 mm

broad, deeply 3-lobed, borne on peduncles to 5 mm long,

cocci ca. 12 x 8 mm, columella 3-6 mm long, to 7 mm

broad distally, with winged erose axis; seeds 7-9 mm

long, 6.3-7.5 mm wide, oblong, smooth, with mottled

coloring.

Plants of wet evergreen cloud forest formations

of the Caribbean slope, ( 1 00-)300-900 m eleva-

tion. Possibly flowering throughout the year; fruit-

ing in December-May. This species ranges from

central Costa Rica (83°28'W) to Venezuela.

Adenophaedra grandifolia is recognized by the

larger oblanceolate leaves on short thick petioles,

gland-tipped dentate leaf margin, unisexual spi-

ciform inflorescences, and minute flowers. Com-

pare the superficially similar Caryodendron an-

gustifolium.

Alchornea Swart/

Trees or shrubs, dioecious in Central American spe-

cies, glabrous or puberulent with simple or stellate hairs;

stipules free, small or obscure. Leaves alternate, simple,

petioles usually thickened near the blade; leaf blades

BURGER & HUFT: FLORA COSTARICENSIS

59

usually dentate with small rounded teeth, venation pin-

nate or palmate (tripliveined), usually with glands in the

leaf tissue near the base, domatia present or absent. Male

inflorescences axillary, 1-3/node, spicate or with simple

lateral branches, <? flowers many, subsessile or short-

pedicellate on the spicate axes, bracts subtending 1-6

flowers; $ flowers with perianth globose to oblate in bud,

splitting into (2-)3-4(-5) valvate calyx lobes, petals ab-

sent, disk absent or confluent with stamen bases, stamens

usually 8 in Central America, in 2 whorls of 4, filaments

free, usually shorter than the anthers, anthers oblong and

dorsifixed, dehiscing longitudinally, introrse; pistillode

absent. Female inflorescences axillary or terminal, usu-

ally I/node, usually spicate with an unbranched rachis

or sometimes with a few basal branches, bracts usually

subtending solitary (2-3) flowers, pedicels short or ab-

sent; 9 flowers with usually 4 (3-6) imbricate sepals,

petals absent, staminodes absent, disk absent; ovary with

2 (3-4) locules, ovules 1/locule, styles 2 (3-4), united

only near the base, style branches rarely bifid at apex.

Fruits capsules with fleshy exterior, globose, usually

splitting into 2 2-valved cocci, columella present but

caducous; seeds tuberculate, ecarunculate, with promi-

nent ventral raphe, endosperm present, cotyledons

straight.

A pantropical genus of ca. 50 species. The genus

is distinguished by its dioecious plants, flat round-

ed glands near the lamina base, frequent presence

of domatia in vein axils, and subsessile flowers

and fruits on long slender few-branched axes. The

inflorescences are either simple and spiciform or

panicle-like with spiciform branches. Individual

collections vary considerably within species, and

this often makes identification difficult.

Key to the Species of Alchornea

1 a. Largest leaves < 6 cm long (in Costa Rica) [subcoriaceous and glabrous, rounded or bluntly acute

distally, venation tripliveined or pinnate; rarely collected from 900 to 1 900 m in Costa Rica and

Panama] A. triplinervia

Ib. Largest leaves > 6 cm long 2

2a. Leaves drying chartaceous, grayish green to dark green 3

2b. Leaves drying coriaceous or subcoriaceous, often yellowish or dark gray [venation pinnate or sub-

palmate] 4

3a. Venation pinnate, basal 2° veins not prominent and not reaching the middle of the blade, leaf

blades usually elliptic to oblong; young stems glabrous; 0-800 m elevation . . A. costaricensis

3b. Venation palmate or subpalmate, basal 2° veins prominent and reaching the center of the blade,

leaf blades usually ovate to ovate-elliptic; young stems densely puberulent; 500-1200 m ele-

vation A. glandulosa

4a. Leaf blades 5-24 cm wide, usually broadly ovate to oblong (elliptic-oblong in the lowlands); style

branches to 0.6 mm wide; commonly collected in Central America, 40-2300 m elevation

A. latifolia

4b. Leaf blades 2-7.5 cm wide, usually narrowly ovate; style branches to 1 mm wide; rarely collected

in Central America at 1600-2200 m elevation A. grandiflora

Alchornea costaricensis Pax & K. Hoffm., Pflan-

zenreich 4. 147. 7: 235. 1914. A. costaricensis f.

longispicata Pax & K. Hoffm., Pflanzenreich 4.

147. 14: 20. 1920. Figure 12.

Trees 4-1 5(-27) m tall, trunks usually less than 30 cm

diam. (to 70 cm), branchlets terete and glabrous; stipules

to 0.5 mm long, triangular. Leaves with petioles 13-35

(80) mm long, 0.7-1.5 mm thick, to 1.8 mm thick near

the blade, glabrous or minutely papillate-puberulent; leaf

blades 7-18 cm long, 3-6.5 cm wide, elliptic to ovate-

elliptic or elliptic-obovate, apex long-acuminate, tip 1-

3 cm long, margin prominently serrate with teeth 5-15

mm apart, base acute to obtuse, glands often on the edge

at the base, drying chartaceous, glabrous above, glabrous

or minutely (0.05 mm) papillate-puberulent beneath, ve-

nation pinnate, 2° veins 5-8/side. Male inflorescences

1-3/axil, 4-8 cm long, unbranched spikes (rarely with

short basal branches), rachis 0.3-0.5 mm thick, minutely

stellate puberulent, flowers in sessile glomerules of 2-5;

$ flowers white or yellowish, buds 1.2-1.5 mm diam.;

filaments short (0.3 mm) and untied at base, anthers 0.5-

0.6 mm long, 0.4 mm wide. Female inflorescences I/

axil, 2-5(-10) cm long, unbranched (or branched when

distal leaves fail to develop), rachis 0.5-0.7 mm thick,

minutely puberulent; 9 flowers solitary, subsessile, calyx

lobes 4, ca. 1 mm long, ovary 1-1.5 mm long, 0.7-1 mm

diam., densely puberulent, styles 7-10 mm long, ca. 0.4

mm thick. Fruits 5-7 mm long, 6-9 mm wide, rounded

and bilobed, pinkish green to reddish brown, pedicels to

3 mm long; seeds 4-6 mm diam., subglobose, surface

irregularly rugose.

Plants of lowland rain forest formations, 0-800

m elevation. Flowering in January-June; fruiting

in March-July. This species ranges from the Ca-

60

FIELDIANA: BOTANY

ribbean coast of Honduras to eastern Panama and

Colombia.

Alchornea costaricensis is distinguished by its

chartaceous serrate glabrescent leaves with pin-

nate venation, simple (rarely branched) $ spikes,

and lowland habitat. It has been called fosforo in

Costa Rica. This species is similar to A. glandu-

losa, but that species has palmate venation and 3°

veins that are more prominent and often conspic-

uously parallel. Specimens of two tall (27 m) trees

from mangrove forest in Honduras appear to be

this species (Saunders 914 & 931). These plants

are easily mistaken for species of Sorocea (Mo-

raceae).

Alchornea glandulosa Poepp. in Poepp. & Endl.,

Nov. gen. sp. PL 3: 18, t. 221. 1841. A. pittieri

Pax, Bot. Jahrb. Syst. 33: 291. 1903. A. glan-

dulosa var. pittieri (Pax) Pax, Pflanzenreich IV.

147. VII (Heft 63): 235. 1914. Figure 24.

Trees 8-22 m tall, leafy stems 1.5-5 mm diam., dense-

ly hirsutulous with short (0.1-0.3 mm) simple and stel-

late hairs; stipules 0.5-1 .5 mm long, hirsutulous. Leaves

with petioles 1.3-5(-7) cm long, 0.7-1.5 mm thick, ca.

1.9 mm thick near the apex, stellate hirsutulous; leaf

blades 5-16.5 cm long, 2-9 cm wide, ovate-elliptic to

elliptic, ovate or narrowly ovate, tapering gradually to

the acuminate apex, tip 4-17 mm long, marginal teeth

8-17/side, rounded, base obtuse to rounded and slightly

subcordate, with 2-6 flat rounded glands in the blade

near its base, drying chartaceous, glabrescent above ex-

cept for small hairs on the midvein, minutely (0. 1 mm)

stellate-puberulent beneath, with tufted domatia in ma-

jor vein axils beneath, venation palmate with basal 2°

veins reaching the middle of the blade, distal 2° veins

2-3/side, 3° veins subparallel. Male inflorescences 5-12

cm long, spicate or with lateral branches to 4 cm long,

rachis 0.5-0.8 mm diam., glomerules with 2-5 subsessile

flowers; $ flower buds 1 .2 mm diam., anthers ca. 0.5 mm

long. Female inflorescences 4-17 cm long, unbranched

spikes (rarely branched), rachis 0.6-1 mm thick, stellate-

puberulent, flowers sessile and solitary; $ flowers with

calyx lobes ca. 0.5 mm long, ovary 1.5-2 mm long, 1.2-

2.2 mm diam., ovoid, densely white or yellowish stellate-

pubescent, styles 5-7 mm long, 0.3-0.4 mm thick; pu-

berulent along abaxial side. Fruits 5-6 mm long, 7-8

mm wide, bilobed, becoming dark; seeds with reddish

covering.

Plants of evergreen lower montane forest for-

mations; 500-1500 m elevation. Flowering occurs

in January-March and September-October; fruit-

ing in October-December. This species ranges from

Costa Rica to the Amazon basin.

Alchornea glandulosa is recognized by the char-

taceous ovate leaves with as many as six small

glands imbedded in the blade near the base, stel-

late-pubescent young stems, and mid-elevation

habitats. Collections from Costa Rica and Panama

belong to variety pittieri, distinguished by smaller

glands than those found in typical South American

collections.

Alchornea grandiflora Mull. Arg., Linnaea 34: 170.

1865.

Trees 6-25 m tall, leafy stems 1.6-5 mm thick, with

scattered minute (0.05-0. 1 mm) flat stellate hairs, gla-

brescent and drying dark; stipules 0.5-1 mm long, tri-

angular. Leaves with petioles 17-65 mm long, 1-2 mm

thick, glabrous and drying dark; leaf blades 5-13 cm

long, 2-7.5 cm wide, broadly elliptic to ovate, apex ob-

tuse, marginal teeth 7-1 I/side, prominent, base cuneate

to obtuse, margin often recurved near the petiole, drying

subcoriaceous, glabrescent above and below, venation

palmate with basal 2° veins reaching middle of the blade,

distal 2° veins 3-4/side, 3° veins prominent and sub-

parallel, basal vein axils forming cavities beneath, distal

vein axils with tufted domatia. Male inflorescences 2-

1 1 cm long, with lateral branches 1-4 cm long, central

rachis 0.5-1 mm thick, bracts ca. 1 mm long; $ flower

buds 1.5-2 mm diam., calyx lobes ca. 1 mm long, tri-

angular, glabrous except on edge, stamens 6-8. Female

inflorescences 4-6 cm long, unbranched, rachis 0.6-1.4

mm thick, with ca. 6-12 flowers, 2 flowers with calyx

lobes to 1 .8 mm long, acute, ovary 1.5-2 mm long, densely

pubescent, style branches 4-18 mm long, ca. 1 mm wide.

Fruits 6-7 mm long, ca. 8 mm wide, bilobed, columella

ca. 5 mm long, 0.8 mm broad.

Plants of montane and lower montane evergreen

forest formations, 1 600-2200 m elevation in Pan-

ama (400-2300 m in South America). Flowering

in June-July in Panama. This species is said to

range from Costa Rica to Bolivia (see below).

Alchornea grandiflora is recognized by its 9 flow-

ers with thick style branches, larger fruits, stiff gla-

brous leaves with prominent domatia, and unusu-

al leaf bases. In larger leaves, the basal secondary

veins have deep depressions in their axils and the

leaf margin is re volute. We have not seen material

from Costa Rica, but a syntype (Hoffman 530 G)

was collected in Costa Rica and several collections

are cited from Panama (Webster & Huft, 1988).

This species can be mistaken for A. latifolia, but

that species tends to grow at lower elevations in

southern Central America.

Alchornea latifolia Sw., Prodr. 98. 1788. Fl. Ind.

Occ. 2: 1 154, t. 24. 1800. A. platyphylla Mull.

Arg., Linnaea 34. 171. 1865 (fide Standl. 1937

who may not have seen the type: Oersted, Ta-

caca, Centr. Amer., herb. B). A. cyclophylla Cro-

izat, J. Arnold Arbor. 24: 166. 1943. Figure 24.

Trees 6-25 m tall, trunks to 45 cm diam., leafy stems

2-7 mm thick, glabrous or with minute (0. 1 mm) scurfy

BURGER & HUFT: FLORA COSTARICENSIS

61

hairs; stipules 1 mm long and triangular or obscure. Leaves

with petioles 2.5-8(-13) cm long, 1.5-2.7 mm thick, to

4 mm thick below the blade, usually glabrous, drying

dark, glands absent on the petiole but 2-4 glands present

in the leaf tissue near the base of the blade; leaf blades

8-24(-34) cm long, 5-19(-24) cm wide, ovate to ovate-

oblong or ovate-orbicular (elliptic-oblong at lower ele-

vations), apex rounded to obtuse, with a small (0-5 mm)

acuminate tip, marginal teeth 8-20/side, 1-2 mm high,

base obtuse to rounded and truncate or subcordate, dry-

ing coriaceous, glabrous above, glabrous or with scat-

tered minute (0.05 mm) flat stellate hairs beneath, ve-

nation palmate or subpalmate (pinnate at lower eleva-

tions), basal 2° veins reaching middle of blade (at higher

elevations), 2° veins 5-7/side, 3° veins subparallel, tufted

domatia or gland-like areas sometimes present in the

leaf axils. Male inflorescences to 30 cm long, paniculate

with few to many alternate unbranched lateral branches

1-9 cm long, rachis 1.2-2.2 mm thick, glomerules with

3-7 flowers; $ flower buds ca. 1.5 mm diam., anthers

0.8-1.2 mm long, 0.6-0.8 mm wide. Female inflores-

cences 5-20(-50) cm long, unbranched or with few to

many branches to 15 cm long, rachis 2-3 mm thick,

minutely stellate puberulent, bracts to 1 mm long, tri-

angular, pedicels 0.5-1.5 mm long; 9 flowers with calyx

lobes ca. 1 mm long, acute, sparsely and minutely pu-

berulent, ovary 1.5-2.5 mm long, 1-2 mm diam., style

column 2-3 mm long, style branches 7-1 1 mm long,

0.4-0.5 mm wide, white. Fruits 5-7 mm long, 7-1 1 mm

wide, bilobed, becoming red; seeds 5-6 mm long.

Plants of lower montane evergreen forest for-

mations, (40-)300-1600(-2300) m elevation.

Flowering in January-July; fruiting in March-Sep-

tember. This is the most commonly collected spe-

cies ofAlchornea in Costa Rica, with most spec-

imens from above 800 m elevation. This species

ranges from Mexico and the West Indies to Ven-

ezuela and Peru.

Alchornea latifolia is distinguished by its larger

broad coriaceous leaves, larger paniculate $ inflo-

rescences with spike-like distal branches, and

rounded fleshy fruits terminated by two persisting

style branches. The highland collections with their

broadly ovate leaves, subpalmate venation, and

usually simple $ inflorescences differ strikingly from

specimens collected below 500 m elevation with

elliptic-oblong leaves, pinnate venation, and <3 in-

florescences with many lateral branches. There ap-

pears to be an altitudinal cline in southern Central

America, with specimens from 500 to 900 m being

intermediate between the highland and lowland

collections, but this pattern may be obscured by

considerable individual variation.

Alchornea triplinervia (Sprengel) Mull. Arg. in DC.,

Prodr. 15 (2): 909. 1866. Antidesma tripliner-

vium Sprengel, Neue Entdeck 2: 116. 1821. A.

guatemalensis Lundell, Wrightia 6: 10, pi. 20.

1978.

Trees 6-20 m tall, leafy stems 1.5-5 mm thick, essen-

tially glabrous; stipules rudimentary. Leaves with peti-

oles 8-22 mm long, 0.7-1 .3 mm thick, slightly thickened

at apex and base, glabrous; leaf blades 3-6 cm long, 2-

3 cm wide, broadly elliptic-oblong to elliptic-obovate,

apex rounded to bluntly acute, margin entire or with 4-

5 small rounded teeth, base rounded to obtuse, with 2-

6 round flat glands near the base, drying subcoriaceous

and grayish, glabrous above and below, venation pinnate

with prominent basal 2° veins but these not reaching the

middle of the blade, 2° veins 3-5/side. Male inflores-

cences to 10 cm long, with lateral branches to 3.5 cm

long, rachis 0.5-1 mm thick, stellate-puberulent, glom-

erules with 1-4 sessile flowers; <3 flower buds 1-1.5 mm

diam., anthers ca. 0.8 mm long. Female inflorescences

to 8 cm long, rachis 0.6-0.8 mm thick, with minute

stellate or scurfy hairs, bracts 0.5 mm long; 9 flowers

solitary, calyx 1.2-1.8 mm long, lobes 0.8-1 mm long,

glabrous, ovary 1-1.5 mm long, 0.6-1 mm diam., with

minute stellate hairs, style branches 3-7 mm long, 0.4-

0.5 mm thick. Fruits ca. 3 mm long, to 5.5 mm wide.

Rarely collected plants of montane (1600-1900

m) forests in Costa Rica but from lower (500-900

m) elevations in Guatemala and Panama. Flow-

ering in June-September; fruiting in September.

In Costa Rica, the species is only known from near

Desamperados, Altos de Tablazo (Utley & Utley

3039 & 5209 F), and Monteverde (Haber 551 CR,

F). It is also known from a single collection in

Guatemala (Lundell & Contreras 21201 F, isotype

of A. guatemalensis) and several collections from

Panama. The species ranges to eastern Brazil.

Alchornea triplinervia is recognized by its small

stiff glabrous leaves with three prominent basal

veins, short 9 sepals, and restricted habitat. The

decision to place these few Central American col-

lections under A. triplinervia and to submerge A.

guatemalensis should be considered tentative.

Alchorneopsis M tiller Argoviensis

Trees, often becoming part of the forest canopy, di-

oecious, hairs simple; stipules absent. Leaves alternate,

simple, petioles with slightly thickened tissue at base and

apex, blades with flat glands near the base, entire or

subentire, venation tripliveined, pit domatia sometimes

present in the vein axils beneath. Inflorescences axillary,

1-3/axil, unisexual, spiciform with long slender un-

branched rachis, flowers or glomerules not crowded along

the rachis, subtended by minute bracts; <5 flowers in al-

ternate glomerules of 1-5 pedicellate flowers, 9 flowers

solitary or few along the rachis, pedicellate. Male flowers

small, globose in bud, calyx splitting into 3-4 valvate

parts, petals absent, disk large and annular, hirsutulous;

stamens 4-8, often 6 in 2 whorls, filaments free, anthers

dehiscing longitudinally and introrse, outer thecae valves

larger than the inner, connective enlarged and glandular;

pistillode minute, 3-lobed, glabrous. Female flowers small,

sepals 4-5, petals absent, disk annular (often difficult to

62

FIELDIANA: BOTANY

see), hirsutulous and merged with the base of the ovary,

staminodes absent; ovary 3-locular, ovules 1/locule, style

column short, style branches 3, recurved and undivided,

papillate. Fruits capsular, small, rounded and breaking

into 3 cocci split only at the apex, columella persistent

or not; seeds flattened, ecarunculate, outer coat fleshy,

inner coat striate-reticulate, cotyledons broad and flat.

A tropical American genus of three closely re-

lated species. The genus is very similar in ap-

pearance ioAlchornea, but it lacks the stellate hairs

of Alchornea. In addition, $ inflorescences of Al-

chorneopsis are never branched and the <3 flowers

have a small pistillode. Seeds of the two genera

are very different, and the three short styles of

Alchorneopsis differ from the typically two long

styles of Alchornea.

Alchorneopsis floribunda (Benth.) Mull. Arg., Lin-

naea 34: 156. 1865. Alchornea glandulosa var.

floribunda Benth., Hooker's J. Bot. Kew Gard.

Misc. 6: 331. 1854. Figure 24.

Trees (3-) 10-40 m tall, trunks to 1 m dbh, brownish

with vertical fissures, leafy stems 1.5-3.5 mm thick, mi-

nutely (0.05-0. 1 mm) puberulent, glabrescent and pale

brown to dark gray; stipules none. Leaves with petioles

10-42 mm long, 0.8-2 mm thick, usually glabrous, slightly

thickened and drying darker near the base and apex; leaf

blades 7-18 cm long, 2-7 cm wide, elliptic, elliptic-ob-

long or oblong-obovate, apex short-acuminate with blunt

tip 4-10 mm long, cuneate to acute at the base, margin

crenate with 6-12 gland-tipped lobes 0.3-1 mm high,

drying stiffly chartaceous to subcoriaceous, glabrous above

and below or very minutely puberulent on the midvein,

2° veins 2-4/side with the basal pair strongly ascending

and reaching beyond the middle of the blade, 3° veins

subparallel and mostly perpendicular to the midvein, flat

rounded glands sometimes present near the base, narrow

slit-like pit domatia (0.5-1 .2 mm long) sometimes pres-

ent in the basal vein axils beneath. Male inflorescences

5-14 cm long, rachis 0.5-0.8 mm thick and minutely

puberulent, with alternate fascicles of 1-7 flowers on

pedicels 1-2 mm long, subtended by bracts ca. 0.5 mm

long; $ flowers white to pale yellowish green, ovoid in

bud and 1.1-1.3 mm long, sepals 1.1-1.5 mm long, re-

flexed, sparsely puberulent on the exterior, glabrous on

the interior, disk 0.3-1 mm high including the erect whit-

ish or yellowish hairs; stamens usually 6, filaments 0.7-

1 .8 mm long, slender, anthers 0.3-0.6 mm long; pistilode

0.4-0.6 mm long, 3-parted, hidden within the hairs.

Female inflorescences 4-6 cm long, usually I/axil, rachis

ca. 0.6 mm thick, minutely puberulent, pedicels ca. 1

mm long, densely puberulent; $ flowers with sepals 0.3-

0.9 mm long, triangular, ovary ca. 2 x 1 .8 mm, minutely

pubescent, style column ca. 0.2 mm long, style branches

ca. 0.6 mm long. Fruits ca. 4 mm long, 3-3.5 mm diam.,

subglobose, smooth and rounded, splitting into 3 cocci

ca. 3 mm broad; seeds often adhering to each other, 2.2-

2.4 mm long, 2.1-2.5 mm broad, ca. 1.2 mm thick,

ovoid-lenticular, pale yellowish, abaxial surface with 10-

1 2 longitudinal ridges, with a red aril-like seed coat.

Large trees in lowland evergreen rain forest for-

mations on both Caribbean and Pacific slopes, 5-

500 m elevation. Flowering in January-August;

fruiting in March-October. The species ranges from

northern Costa Rica to Peru and Brazil.

Alchorneopsis floribunda is recognized by its

tripliveined gland-tipped crenate leaves, long slen-

der unbranched axillary inflorescences with dis-

tant flowers or clusters of flowers, and unusual

seeds. Additional characters are the longer petioles

drying darker near apex and base and the occa-

sional presence of pit domatia. These trees can

become part of the forest canopy.

Aleurites Forster & G. Forster

Trees, monoecious, with simple or stellate hairs, sap

milky; stipules paired at the node or poorly developed,

caducous. Leaves alternate, simple, petioles long and

with 2 glands at the apex, blades of the young treelets

or early branches often with large lobes, margins entire

or with minute glands or poorly developed serrations (or

sinuses), venation palmate or pinnate. Inflorescences ter-

minal or axillary, open-branched panicles of few-flow-

ered cymes (thyrsiform), bisexual with proximal flowers

mostly $ and distal or terminal flowers 9, pedicels short.

Male flowers with a united calyptrate calyx splitting into

2-3 parts at anthesis, petals 5, longer than the sepals,

imbricate, narrowed at the base, disk 5-lobed; stamens

5-20, from a conical receptacle in 1-4 series, outer 5

stamens opposite the petals and alternating with glan-

dular lobes of the disk; pistillode absent. Female flowers

with perianth similar to <? but caducous, staminodes ab-

sent; ovary with 2-5 locules, ovules 1/locule, styles 2-

5, divided to near the base. Fruits drupaceous or a de-

hiscent 2-5-seeded nut, usually with fleshy exocarp and

bony endocarp.

A genus of six species of China, Southeast Asia,

Malaysia, and the western Pacific. However, Aleu-

rites has also been interpreted as a genus of only

two species (cf. Webster, 1 994b, p. 1 1 4). A number

of species are now grown throughout the tropics

and subtropics for the seeds, which produce drying

oils. Two species are commonly planted in Latin

America. Larger leaves of young plants are often

deeply lobed. The paired glands at the apex of the

petiole, palmate venation, spatulate petals, and

drupaceous fruits help distinguish the genus.

la. Puberulence of simple hairs, usually sparse; flower buds 8-12 mm long, glabrous; ovary 3-5-locular

A. fordii

BURGER & HUFT: FLORA COSTARICENSIS

63

Ib. Puberulence of scurfy stellate hairs, often dense; flower buds 2-4 mm long; ovary 2-locular

. A. moluccana

Aleurites fordii Hemsl. in Hook., Icon. PI. 29:

2801-2802. 1909.

Trees to 8(-15) m tall, much branched, with smooth

pale gray bark, leafy stems 3-7 mm thick, glabrous or

with few thin hairs to 1 mm long, drying dark with pale

lenticels ca. 1 mm long; stipules 2-4 mm long, caducous.

Leaves deciduous, petioles 7-16 cm long, 1.2-4.8 mm

thick, glabrous, glands 1-4 mm long, 1-3 mm broad,

sessile or stalked, base of dried petiole often contracted

for 3-6 mm; leaf blades 7-17(-24) cm long, 4-14(-23)

cm wide, ovate or with 3 or 5 prominent lobes (sinuses

to 6 cm deep), apex acuminate, margin entire to slightly

undulate, base rounded and truncate to subcordate, gla-

brous and deep green above, glabrous or with thin yel-

lowish hairs to 1 mm long beneath, venation palmate

with 3-5 major veins, 2° veins 5-8/side of the midvein.

Inflorescences dichotomously branched with distal cymes,

with relatively few flowers, to 12 x 18 cm, glabrous,

central terminal flower 9 with the others usually <5. Flow-

ers white, <5 calyx 3-5 mm long, $ calyx 8-12 mm long,

petals 5-17 mm long, to 6 mm wide, spatulate, marked

with pink, with many parallel veins, filaments 12-16 mm

long, anthers ca. 2 mm long. Fruits 4-6 cm long, 5-7

mm diam., subglobose to ovoid, becoming dark brown,

5-locular.

Aleurites fordii originated in western China; it

is found in gardens or special plantings in Central

America. The seeds are the source of tung oil, a

rapidly drying oil that is used for outside protec-

tive paints and waterproofing. The seeds average

50% oil; residue seed cake (from oil-extracted seeds)

is toxic but has been used as a fertilizer. Aleurites

montana is similar and originated in the subtrop-

ical areas of China and Burma; it is better adapted

to the moist tropics than is A. fordii.

Aleurites moluccana (L.) Willd., Sp. PI. ed. 4: 590.

1 805. Croton moluccanum L., Sp. PI. 1005. 1 753.

A. triloba J. R. Forster, Char. gen. pi. ed. 2, 112.

1776.

Trees 6-20 m tall, with spreading or pendulous

branches, wood pale and weak, leafy stems 4-10 mm

thick, densely covered with scurfy-stellate hairs 0.2 mm

broad, becoming pale grayish; stipules ca. 5 mm long,

narrowly triangular, caducous. Leaves with petioles 5-

22 cm long, 1.8-5 mm thick, glabrescent, apical adaxial

glands ca. 1.3 mm wide, disk-like or shallow cups; leaf

blades 1 0-23(-30) cm long, 6-1 7(-27) cm wide, narrowly

to broadly ovate, ovate-triangular or with 1-2 large (2-

3 cm) lobes on each side, apex acute to subacuminate,

rounded and truncated at the base, edge with minute

glands in shallow (0.3 mm) sinuses, very sparsely pu-

berulent above, with minute (0.2 mm) stellate hairs be-

neath, venation palmate with 3 or 5 major veins (sub-

palmate in smaller leaves), 2° veins 4-6/side. Inflores-

cences 6-16 cm long, to 17 cm wide, widely branching

with flowers in distal cymes, densely pubescent with

scurfy-stellate hairs, $ flowers many, 2 flowers few. Flow-

ers densely pubescent, buds ca. 3 mm long, petals 5-6

mm long, 1.3-2.2 mm wide, obovate-oblong; stamens

1 5-20 (in <5); ovary ca. 3 mm long, ovoid, densely stellate-

pubescent, styles 0.5-1 mm long. Fruits 3-6 cm diam.,

subglobose-oblate to ellipsoid, covered with a dense in-

dumentum of appressed stellate hairs 0.1-0.2 mm wide,

olive-green with whitish flesh.

Aleurites moluccana, native to south Asia and

the western Pacific, is now widely cultivated in

tropical regions. It is well adapted to humid trop-

ical environments where A. fordii does not grow

as well. Though poisonous, the seed is used for

making soap and paint. The species is also used

as an ornamental and shade tree, appearing whit-

ish from a distance. It is called nuez and "candle-

nut tree." (See fig. 324 in Correll & Correll, 1982.)

Amanoa Aublet

REFERENCE— W. J. Hayden, Notes on Neotrop-

ical Amanoa (Euphorbiaceae). Brittonia 42: 260-

270. 1990.

Trees or shrubs, monoecious, glabrous, heartwood

reddish to purple-brown, moderately to very dense; stip-

ules intrapetiolar, united above the upper (adaxial) base

of the petiole and forming an oblique-decurrent ligule-

like structure, persistent. Leaves alternate, simple, short-

petiolate, without glands, blades subcoriaceous and en-

tire, pinnately veined. Inflorescences basically of solitary

axillary fascicles or glomerules but these more often al-

ternate on leafless axes that appear spicate or paniculate

(with alternate lateral branches), flowers sessile and sub-

tended by a loose involucre of many imbricate small

bracts (the bracts larger in African species). Male flowers

with 5 unequal imbricate sepals, usually larger than the

small scale-like petals, disk inconspicuous, extrastam-

inal, lobed; stamens 5, opposite the petals, filaments free,

shorter than the anthers, anthers ovoid, dehiscing lon-

gitudinally and introrse; pistillode 3-lobed distally. Fe-

male flowers with 5 sepals, imbricate and subequal, pet-

als small and often scale-like, disk small and 5-lobed,

staminodes absent; ovary 3-locular, globose, ovules

2/locule, styles short and united, stigmas 3, thick and

bifid, reflexed. Fruits woody capsules or drupe-like, sur-

face muricate, endocarp usually thick, tardily dehiscent

into 3 (2, 1) 2-valved cocci, columella large and per-

sisting; seeds 1/locule, ovoid to ellipsoid, smooth and

ecarunculate, endosperm little or none, cotyledons mas-

A small genus with 1 3 species in tropical Amer-

ica and 3 in Africa-Madagascar. Only one species

64

FIELDIANA: BOTANY

is known to occur in southern Central America.

The two ovules per locule place the genus in sub-

family Phyllanthoideae.

Anianoa guianensis Aublet, Hist. pi. Guiane Fr.

256, t. 101. U75.A.potamophilaCroizat,AmeT.

Midi. Naturalist 29: 475. 1943. A. macrocarpa

Cuatrecasas, Brittonia 1 1: 164. 1959. Figure 27.

Shrubs or small trees, 2-7 m tall, leafy stems 2-6 mm

thick, glabrous, brownish, often with elevated lenticels

0.5-1.5 mm long; stipules 0.7-2 mm long, broadly

rounded above the adaxial petiole base, reddish brown,

persisting. Leaves with petioles 4-8 mm long, 0.8-2.5

mm thick, drying dark, glabrous; leaf blades 7-14 cm

long, 2.5-7 cm wide, elliptic, elliptic-oblong, oblong or

obovate, gradually or abruptly narrowed to the short-

acuminate apex, base obtuse to rounded or subtruncate,

drying subcoriaceous and dark grayish brown, glabrous,

2° veins 7-9/side, arising at angles of 60-80°, weakly

loop-connected 5-9 mm from the leaf edge. Inflores-

cences of axillary fascicles or the fascicles often on a

leafless terminal stem-like rachis to 16 cm long, un-

branched or with 1-2 lateral branches, fascicles separated

by 4-1 2 mm along the rachis, subtended by an involucre

of bracts 5x8 mm, distal rachis 1.5-3 mm thick, gla-

brous, bracts ca. 2 x 2 mm. Male flowers with sepals

7-9 mm long, ovate, thick, petals 0.7-1 mm long, disk

1.1-1.4 mm diam., cupulate; anthers ca. 5 mm long;

pistillode ca. 5 x 2.5 mm, 3-lobed. Female flowers with

sepals 7-9 mm long, ovate-oblong, petals 1.5-1.7 mm

long, 2-2.3 mm wide, suborbicular, minutely denticu-

late; pistil 2.5-5 x 2-2.5 mm, ovary and thick stylar

column not differentiated, stigmas ca. 1.3 x 1.8 mm,

sessile, obscurely 2-lobed. Fruits 2-3 cm long, 2.5-3 cm

diam., subglobose, slightly compressed at base and apex,

borne on a thickened pedicel 3-15 mm long, splitting

into 3-6 woody parts, outer wall 3-4 mm thick, colu-

mella 1 5 mm long, 7 mm wide; seeds 1 5 x 13x9 mm,

cordate-triangular in outline, smooth and lustrous, scar

3x2 mm.

Plants of lowland seaside forest formations and

swamp forests, 0-150 m elevation. Flowering in

March and October; fruiting in February-March,

October, and December. This species has been

collected along the Caribbean coast of Belize, Gua-

temala, and Nicaragua and in central Panama. It

ranges southward to the Guianas.

Amanoa guianensis is recognized by its restric-

tion to lowland forests near the seacoast, the flow-

ers in sessile involucrate fascicles on inflorescences

that appear to be leafless branchlets, and thick-

walled woody fruits. The ovaries with two ovules

per locule develop into three-seeded fruits by abor-

tion. Although not yet collected in Costa Rica, it

occurs in adjacent Nicaragua.

Antidesma bunius (L.) Spreng., the "Chinese

laurel," is occasionally cultivated in Central

America. These ornamental shrubs have un-

branched unisexual inflorescences and sweet dru-

paceous fruits with solitary seeds. The 9 flowers

have an annular disc and the ovary is one-locular

with one broad stigma. The male flowers have two

to five stamens, a small pistillode, and four to five

small imbricate calyx lobes. The eglandular leaves

are pinnately veined, entire, and subcoriaceous.

Antidesma, a paleotropical genus of ca. 160 spe-

cies, is closely related to Hyeronima.

Aparisthmium Endlicher

Trees or shrubs, dioecious, pubescence of short simple

hairs; stipules 2, small, lateral. Leaves alternate, petio-

late, with 2 stipel-like appendages at the apex of the

petiole, blades ovate, pinnately veined, serrulate. Male

inflorescences mostly terminal, paniculate, bracts sub-

tending small glomerules of sessile flowers, $ flowers small,

ovoid in bud, calyx splitting into 2-3 valvate sepals,

petals and disk absent; stamens 4 (3, 5), filaments united

at the base, separate in the distal half, anthers longitu-

dinally dehiscent, connective not prolonged; pistillode

absent. Female inflorescences racemose (or with a few

lateral branches), bracts biglandular, subtending 1 (2)

flower; 9 flowers with 4-6 sepals, petals and disk absent,

staminodes absent; ovary 3-locular, ovules 1 /locule, styles

3, united at base and thick, minutely 2-lobed at the apex,

papillate on interior surfaces. Fruits capsules splitting

into 3 2-valved cocci, columella persistent; seeds eca-

runculate, endosperm carnose, cotyledons flat, oblong.

A monotypic genus, until recently, known only

from South America. The recent addition of this

species to the Central American flora is another

example of an Amazonian species disjunct in

southwestern Costa Rica. Continued use of the

generic name will need conservation (Webster,

1994b). The genus is currently being studied by

Ricardo Secco (MG).

Aparisthmium cordatum (Juss.) Baill., Adansonia

5: 3-7. 1865. Conceveibum cordatum Juss., Eu-

phorb. gen. 43, t. 13, f. 42a. 1824. Alchornea

macrophylla Mart., Herb. fl. bras. 24 (beibl 2):

31. 1841. Figure 20.

Trees or shrubs, 3-1 0 m tall, leafy stems 4-9 mm thick,

minutely puberulent with thin hairs 0.1-0.4 mm long;

stipules to 3 mm long, subulate, caducous. Leaves al-

ternate or congested beneath distal flowering nodes, pet-

ioles 1.2-1 1(-18) cm long, 1-2.7 mm thick, minutely

puberulent, with 2 stipel-like structures at the adaxial/

lateral apex, 2 flat rounded glands 1-1.5 mm diam. pres-

ent at the base of the blade in the abaxial surface; leaf

blades (10-)12-24(-32) cm long, 5-15(-19) cm wide,

ovate-elliptic to broadly ovate or ovate-orbicular (small-

er leaves narrowly ovate-elliptic), apex acuminate to cau-

date-acuminate, the narrow tip 1-2.5 cm long, margin

BURGER & HUFT: FLORA COSTARICENSIS

65

crenate or serrate with rounded glandular teeth ca. 1 mm

high (subentire), base rounded and truncate to subcor-

date (cuneate in smaller leaves), drying stiffly charta-

ceous and dark greenish, upper surfaces with minute

(0. 1-0.2 mm) hairs along the major veins, lower surfaces

minutely puberulent or glabrescent, 2° veins 6-1 I/side.

Male inflorescences and flowers not seen. Female inflo-

rescences not seen at anthesis, solitary and axillary or

several from a condensed distal node, 1 6-40 cm long in

fruit, bracteoles ca. 1.5 mm long, triangular, fruits borne

on pedicels 10-18 m long, 0.4-0.9 mm thick, minutely

puberulent. Fruits 6-8 mm long, 8-1 1 mm wide, deeply

3-lobed, sparsely puberulent with minute hairs, sub-

tended by persisting triangular calyx lobes 1.5-2 mm

long, persisting style branches ca. 3 mm long, 0.4-0.5

mm thick, columella 3.8-5 mm long; seeds 4.5-5.5 mm

long, 3.5-4 mm diam., oblong-ellipsoid.

Plants of evergreen forest on the Pacific slope

in southern Costa Rica, ca. 300 m elevation. The

species is known in Central America from a single

collection (Wilbur et al. 23958 DUKE) from about

12 km northeast of Quepos; fruiting in August. In

South America, the species ranges from Colombia,

Venezuela, and the Guianas to Bolivia.

Aparisthmium cordatum is recognized by the

large ovate leaves with bluntly glandular-serrate

margins, minute simple hairs on many surfaces,

long racemose 9 inflorescences, capsular fruits, and

seeds almost circular in cross-section. The two sti-

pel-like structures at the apex of the petiole (not

seen in the Costa Rican collection), two flat round-

ed glands on the abaxial base of the leaf, and the

subparallel 3° veins are additional distinctions.

Specimens may resemble Conceveiba pleioste-

mona, but Aparisthmium lacks the minute stellate

hairs and has dry capsules with smaller seeds.

Argythamnia P. Browne

Shrubs, subshrubs, or small trees (herbs), annual or

perennial, monoecious (rarely dioecious), stems pubes-

cent with appressed slender 2-parted hairs attached at

the center (T-shaped), often with purplish pigment; stip-

ules paired, small, persisting. Leaves alternate, simple,

short-petiolate, blades dentate or entire, venation pin-

nate or palmate (tripliveined), eglandular. Inflorescences

axillary, solitary, racemiform, usually bisexual with 1-3

proximal 9 and several distal 3 flowers, subsessile or

short-pedicellate, each flower subtended by a small bract.

Male flowers with ovoid buds, sepals 5, valvate, petals

5, imbricate but narrowed at the base and adnate to

stamina! column, disk of 5 glands opposite sepals; fertile

stamens 5-15 in 1-3 whorls of 5 each (consistently 10

in 2 whorls in subgenus Ditaxis), united at the base to

form a column, filiform staminodes sometimes present

at the apex of the column, filaments united at base, short,

anthers ovate, dehiscing longitudinally and introrse; pis-

tillode absent. Female flowers with 5 imbricate sepals,

petals 4 or 5, imbricate, usually shorter than the sepals,

entire, staminodes absent, disk cylindrical or dissected

into sometimes elongate segments, filaments or glands;

ovary subsessile, 3-locular, styles 3, free or united at the

base, bifid d i stall y. ovules 1/locule. Fruits often borne

on reflexed pedicels, capsular, 3-lobed, separating into

3 2-valved cocci, leaving a persistent columella; seeds

subglobose, ecarunculate, surface reticulate to foveolate.

A genus (in the wide sense) of ca. 80 Neotropical

species. Our species has also been assigned to Di-

taxis, sometimes considered a subgenus of Argy-

thamnia (cf. Ingram, 1980, and Webster, 1994b).

Argythamnia guatemalensis Mull. Arg., Linnaea

34: 145. 1 865. Ditaxis guatemalensis (Mull. Arg.)

Pax & K. Hoffm. Pflanzenreich 4, 147, 6: 59.

1912. Figure 11.

Herbaceous subshrubs, stems erect or horizontal, 0.5-

1 m tall, from a woody rootstock, leafy stems 0.8-2.8

mm thick, sericeous with slender whitish linear

2-branched hairs attached at the center (but difficult to

see), 1-3 mm long; stipules 1-3 mm long, 0.2-0.5 mm

wide at the base, linear, acute, persistent or deciduous.

Leaves with petioles 0.7-3(-6) mm long, 0.5-1.5 mm

thick, densely sericeous; leaf blades 17-85 mm long, 8-

35 mm wide, ovate-elliptic to ovate-lanceolate or lan-

ceolate, apex acute with minute gland tip, usually cuneate

at the base, margin minutely (0.2-0.5 mm) serrate with

1 2-30 teeth/side, drying chartaceous and grayish, with

hairs 0.3-1 .3 long on the upper surface and shorter dense

hairs beneath, 2° veins 3-4/side and strongly ascending,

becoming impressed above. Inflorescences 6-1 5 mm long,

subglomerulate with few flowers, peduncle 1-5 mm long,

densely sericeous, flowers subsessile or short-pedicellate.

Male flower buds ca. 4 mm long, sericeous, sepals 1.5—

3 mm long, petals 2-2.8 mm long; stamens 10 with 3

small staminodes, anthers orange. Female flowers with

buds ca. 4 mm long, sericeous, sepals 3.5—4.5 mm long,

0.6—1.3 mm wide, narrowly oblong to oblanceolate, pet-

als 1-2 mm long; ovary 2-2.5 mm long, 3-3.5 mm wide,

oblate, short-pubescent, style column 0.7 mm long, style

branches 0.7 mm long. Fruits 4x6 mm, oblate, short-

sericeous, columella 2.2 mm high, I-shaped; seeds 2.5-

3 mm long, 2-2.5 mm wide, surface reticulate with hex-

agonal depressions 0.3-0.5 mm wide.

Plants of the seasonally deciduous lowlands of

northeastern Costa Rica, 0-200 m elevation.

Flowering in February, April, August-October, and

December. The species ranges from Mexico along

the Pacific side of Central America to the Bay of

Nicoya in Costa Rica.

Argythamnia guatemalensis is recognized by the

unusual hairs (attached at the center but difficult

to see), short few-flowered axillary inflorescences,

unisexual flowers, sepals and petals differing only

slightly in length in 6 flowers, herbaceous habit,

and restriction to seasonally deciduous habitats.

The description of this species in the Flora of Gua-

66

FIELDIANA: BOTANY

temala (Standley & Steyermark, 1 949) lists larger

floral parts than those seen in Costa Rica.

Astrocasia Robinson & Millspaugh

REFERENCE— G. L. Webster, Revision of Astro-

casia (Euphorbiaceae). Syst. Bot. 17: 311-323.

1992.

Small trees and shrubs, monoecious or dioecious, gla-

brous; stipules lateral, ribbed with parallel venation, de-

ciduous. Leaves alternate, petiolate, sometimes peltate,

blades entire, pinnately veined, glabrous. Inflorescences

axillary, flowers in fasciculate glomerules of few to many

6 flowers or 1-3 9 flowers, subtended by stipule-like bracts,

borne on long thin glabrous pedicels. Male flowers gla-

brous, sepals 5, free, usually unequal with outer smaller

and thicker, imbricate in bud, petals 5, free, longer than

the sepals, disk annular or patelliform; stamens 3-5, fil-

aments united to form a column, anthers sessile or stip-

itate on the column, 2-thecous, lateral on the flattened

apex of the column, dehiscing horizontally or deflexed,

pistillode sessile or stipitate on the dilated apex of the

staminal column. Female flowers glabrous, sepals 5, free,

imbricate in bud, deciduous, petals 5, free, larger than

the sepals, staminodes absent; disk annular to cupular,

entire or slightly lobed; ovary 3- (rarely 4)-locular, ovules

usually 2/locule, anatropous, styles 3 or 4, short and

united at the base, branches short and bifid. Fruits cap-

sules, thin-walled separating into 3 (4) 2-valved cocci,

columella persisting, slender; seeds 1/locule, smooth,

ecarunculate, raphe conspicuous, endosperm copious,

cotyledons thin, flat.

A Neotropical genus of five species ranging dis-

junctly from Mexico and the West Indies to Brazil

and Bolivia. The unisexual plants, lack of pubes-

cence, deciduous leaves, flowers from distal stems

on long thin pedicels, free petals, peltate androe-

cium, cupulate 9 disk, and capsular fruits help dis-

tinguish this genus. In a 9 flower we dissected, there

was only one ovule per locule, with some indi-

cation that the second ovules had failed to devel-

op.

Astrocasia tremula (Griseb.) Webster, J. Arnold

Arbor. 39: 208. 1958. Phyllanthus tremulus Gri-

seb., Fl. Brit. W. Ind. 34. 1859. Astrocasia phyl-

lanthoides Robins. & Millsp., Bot. Jahrb. Syst.

36, Beibl. 80: 19. 1905. Figure 32.

Small trees or shrubs 1.5-6(-10) m tall, dioecious (or

monoecious), leafy stems 0.7-3 mm thick, glabrous, be-

coming pale grayish with elliptic lenticels; stipules 4-9

mm long, ca. 1.5 mm wide at base, narrowly triangular,

glabrous, yellowish, venation parallel, caducous. Leaves

deciduous, glabrous, petioles (4-) 12-68 mm long, 0.5-

1.5 mm thick, sometimes thickened (geniculate) at apex

and base, with 1 or 2 small (0.3-0.7 mm) glands/stipels

at apex adaxially (at base of mature blade); leaf blades

3.5-10(-14) cm long, 2.5-6(-9) cm wide, ovate to ovate-

rhombic or ovate-elliptic, apex obtuse or acute, margins

entire (slightly undulate when dried), base broadly ob-

tuse, drying membranaceous (flowering material) to

chartaceous, glabrous, 2° veins 3-7/side. Male inflores-

cences from axillary short-shoots 2-6 mm long, fascic-

ulate with 5-20 flowers, glabrous, bracts 2-3 mm long,

with parallel venation, pedicels 8-18 mm long, 0.1-0.2

mm thick; $ flowers 3-4 mm wide, sepals 0.7-1.3 mm

long broadly elliptic to obovate, entire, petals 1.5-3.5

mm long, oblong, disk often obscure, 0.9-1.8 mm wide;

staminal column 0.3-0.4 mm long, ca. 0.2 mm thick,

terminated by a peltate flat apex 0.8-1.1 mm wide, with

5 stamens represented by 1 0 thecae borne along the outer

rounded periphery, anthers ca. 0.3 mm high; pistillode

sessile on the staminal column. Female inflorescences of

1-5 flowers in axils of leaves or fallen leaves, glabrous,

pedicels 2-5 cm long, 0.4-0.7 mm thick; 9 flowers ca. 4

mm long, glabrous, sepals 1.7-2.5 mm long, petals 3.5-

4.2 mm long, 1.3-1.7 mm wide, obovate to spatulate,

rounded distally, disk forming a thin cup 0.5-1 mm high

and ca. 2.2 mm ilium.; pistil ca. 2 mm long, ovary ca.

1.2 mm diam., styles ca. 0.6 mm long. Fruits 8-9 mm

long, 10-12 mm wide, oblate, with 3 rounded lobes,

glabrous, persisting stigmas ca. 0.4 mm long, columella

3.5-5 mm long, I-shaped; seeds 4-5 mm long, 3.3-4 mm

wide, ca. 3 mm thick, irregularly rounded to wedge-

shaped, smooth, uniformly yellowish or dark brown.

Plants of the evergreen Caribbean lowlands, 20-

500 m elevation. Fruiting in October-March.

Known in Costa Rica only from Bajo Rodriguez

(north of San Ramon), Alajuela (Gomez- Laurito

12368 usj). The species is usually found on lime-

stone and ranges disjunctly from southeastern

Mexico, Belize, Guatemala, Jamaica, central Pan-

ama, and northern South America to eastern Bra-

zil.

Astrocasia tremula is recognized by its complete

lack of pubescence, usually dioecious plants, few

flowers on slender pendulous pedicels arising from

the stems or short-shoots, well-differentiated se-

pals and petals, and unusual peltate androecium

on which the thecae form a 10-lobed margin.

Flowering appears to occur with the flush of new

foliage. This species is closely related to A. peltata

Standley of Mexico.

Bernardia Miller

Shrubs or small trees, monoecious or dioecious, pu-

bescence of simple or stellate hairs; stipules small. Leaves

alternate, simple, petiolate to subsessile, pinnately or

palmately 3-veined, margins dentate, often with 2 glan-

dular areas near the base of the blade, without stipels.

Inflorescences unisexual and solitary, ,', axillary or pseu-

doterminal, short or long spikes, bracts subtending 1-7

sessile or short-pedicellate flowers; 9 terminal or axillary

to distal leaves, flowers aggregated (and few-flowered) or

BURGER & HUFT: FLORA COSTARICENSIS

67

sessile on spikes, each concave bract subtending 1 9 flow-

er. Male flowers globose in bud, calyx splitting into 3-

5 valvate sepals, petals absent, disk usually of minute

elements among stamens bases; stamens 3-30, filaments

free, slender, short, anthers 2- or 4-lobed (emarginate),

dehiscing longitudinally, thecae subglobose; pistillode

small or none. Female flowers with 4-6 imbricate sepals

(and subtended by similar bracts), petals absent, disk

annular or of separate glands, staminodes absent; ovary

3-locular, ovules 1/locule, style column short, branches

2-lobed, simple to lacerate. Fruits capsular, breaking into

3 2-valved cocci, columella persisting; seeds carinate,

rounded to prismatic, ecarunculate, endosperm carnose.

A tropical American genus of ca. 50 species,

with the majority of species in Brazil and a second

center of diversity in Mexico. Our two species are

quite different in appearance and habitat.

Key to the Species of Bernardia

la. Plants of evergreen montane forest formations; leaves elliptic-oblong to lanceolate, to 20 cm long;

pubescence mostly of simple hairs B. macrophylla

Ib. Plants of deciduous forest formations of Guanacaste; leaves ovate, to 1 1 cm long, pubescence of

stems and leaves mostly of stellate hairs B. nicaraguensis

Bernardia macrophylla Standl., J. Wash. Acad. Sci.

15: 103. 1925. Figure 12.

Shrubs 1.5-3 m tall, monoecious, leafy stems 1-4 mm

thick, appressed-pubescent with thin simple ascending

hairs 0.2-0.5 mm long; stipules 1.2-1.9 mm long, 0.5-

1 mm broad at the base, narrowly triangular, persistent.

Leaves with petioles 3-10 mm long, 0.5-1 mm thick,

densely appressed-hispidulous, glands absent; leaf blades

6-16(-20) cm long, 1.5-5(-7.5) cm wide, narrowly ellip-

tic-oblong to narrowly elliptic or lanceolate, tapering

gradually to the acuminate apex, margin with gland-

tipped serrations 0.2-0.7 mm high, 1 5-40/side, base acute

and slightly decurrent on the petiole, drying chartaceous,

2° veins 7-1 1 /side, arising at 30-40°. Male inflorescences

2.5-7 cm long, often axillary to older leaves, peduncles

2-3 cm long, appressed-puberulent, 0.7 mm thick, glom-

erules 1 .4-5 mm distant along the rachis, with 3-6 flow-

ers, bracts ca. 1 x 2 mm, pedicels 1-1.5 mm long; $

flower buds 1.3 mm diam., sepals 1.2-1.8 mm long, 0.7-

1.1 mm wide, lanceolate, disk represented by minute

clavate glands; stamens ca. 1 5, filaments 0.7-1 mm long,

slender, anthers 0.2 x 0.4 mm. Female inflorescences in

axils of distal leaves, 5-25 mm long, densely pubescent,

peduncle ca. 2 mm long, flowers few, subtended by bracts

ca. 2 mm long; 9 flowers pubescent, sepals 5, 1.6-1.8

mm long, 0.8-1.3 mm wide, ovate, disk 0.2-0.3 mm

high, glabrous; ovary 1-2 mm long, style branches 0.4

mm long. Fruits ca. 7 x 8 mm, yellowish, rugulose,

sparsely minutely puberulent.

Plants of evergreen forest formations; known

from 1 800 m elevation in easternmost Costa Rica

but collected near sea level in Panama (Standley

29389 us holotype). Flowering and fruiting in

March in Costa Rica (Davidse et al. 25611 CR, MO).

The species is known only from the collection cited

above and a few collections in Panama.

Bernardia macrophylla is recognized by its long

slender $ spikes, narrow dentate leaves, simple

hairs, and unisexual flowers. Webster and Burch

(1967) describe the species as dioecious, but our

material is clearly monoecious. This species should

be reexamined when more material becomes

available.

Bernardia nicaraguensis Standl. & L. O. Wms.,

Ceiba 1: 85. 1950. Figure 12.

Shrubs or small trees, 2-8 m tall, dioecious, leafy stems

1.5-4 mm thick, stellate-tomentulose with yellowish hairs

0.2-0.8 mm long, glabrescent and dark grayish in age,

terete; stipules 2.5^4 mm long, 1 mm wide at the base,

lanceolate, deciduous. Leaves with petioles 4-17 mm

long, 0.8-1.6 mm thick, densely stellate-tomentulous;

leaf blades 3-12 cm long, 2-8 cm broad, ovate to ovate-

elliptic or broadly elliptic, apex obtuse to acute, margin

irregularly crenate-dentate with 1 5-35 teeth/side 0.3-1 .5

mm high, base obtuse to somewhat rounded and sub-

truncate, drying chartaceous and darker above, scabrous

with stellate hairs ca. 0.3 mm long above, with dense

stellate hairs 0.3-0.8 mm diam. beneath, 2° veins 4-67

side, subpalmate with the basal 2° veins often reaching

the middle of the blade, central 2° veins arising at angles

of 40-50°. Male inflorescences 12-40 mm long, 3-5 mm

wide, at first erect and cone-like, bracts 2-3 mm long,

broadly ovate, with dense straight hairs ca. 0.3 mm long;

$ flowers with 4 sepals 2.5 x l mm, densely tomentulous

on the exterior but glabrous on the inner surface; stamens

ca. 20, filaments 1-1.8 mm long, filiform, glabrous, an-

thers 0.3-0.4 mm long. Female inflorescences to 5 cm

long with 2-5 sessile flowers, peduncle to 14 mm long,

densely stellate-tomentulous, bracts ca. 1.3 mm long; 9

flowers with sepals ca. 3 x 2 mm, stiff; ovary 3-4 mm

diam., globose, densely yellowish hirtellous, style branches

1.5 mm long. Fruits ca. 7.5 x 11 mm, deeply 3-lobed,

densely stellate-tomentulose, walls of cocci 0.2-0.3 mm

thick, columella 4-5 mm long, 2-4 mm wide; seeds 5.5-

6.5 mm long, 4.5—4.7 wide, 4.2-4.5 mm thick, ovoid-

angular, grayish brown or mottled.

Plants of open savanna formations, deciduous

and partly deciduous forest formations, 20-1200

68

FIELDIANA: BOTANY

m elevation (to 1400 m in Nicaragua). Flowering

in January-May; fruiting in February-August. The

species ranges from Honduras to northwestern

Costa Rica.

Bernardia nicaraguensis is recognized by its sea-

sonally very dry deciduous habitat, dense covering

of slender stellate hairs, ovate denticulate leaves

with subpalmate venation, and distal leaf axils with

tomentulose cone-like 3 inflorescences (in early

stages) or more elongate few-flowered 2 spikes. The

plants may lose their leaves as flowering progresses

(Haber & Zuchowski 10483).

1 5 mm long (flowers sometimes borne in small groups

on leafless axillary branches to 3 cm long); <5 calyx tur-

binate; 9 calyx campanulate and lobed.

Breynia disticha, native of the New Herbrides,

is often planted as an ornamental bush or in hedges

in tropical gardens. The reddish stems with many

small variegated leaves marked with green, white,

red, or pink give a colorful effect. It is called "snow

bush" and "leaf flower."

Caperonia St. Hilaire

Breynia J. R. & G. Forster

(nom. conserv.)

Shrubs or small trees, monoecious, distal leaf-bearing

stems resembling pinnate leaves. Leaves alternate and

distichous, simple, short-petiolate, blades entire, pin-

nately veined, often blackening on drying. Inflorescences

axillary, flowers small, solitary or few in fascicles ($), or

on leafless unbranched axillary shoots, <5 pedicels slender.

Male flowers with a turbinate calyx, calyx lobes 6, im-

bricate and rounded, petals and disk absent; stamens 3,

filaments united, anthers elongate; pistillode absent. Fe-

male flowers with 6 calyx lobes, imbricate, petals and

disk absent; ovary 3-locular, ovules 2/locule, styles 3,

free, bifid or simple. Fruits somewhat fleshy, incom-

pletely dehiscent; seeds trigonous, with fleshy outer seed

coat, ecarunculate.

A genus of 10-25 variable species in eastern

tropical Asia and the Pacific. The genus is closely

related to Phyllanthus but differs in the ventrally

invaginated seeds with fleshy exotesta and the lack

of a floral disk. Varieties of one species are widely

cultivated in the tropics as ornamental shrubs.

Herbs or subshrubs, annual or perennial, monoecious

(in Central America), usually growing in wet places, with

simple or gland-tipped hairs; stipules paired at the leaf

base. Leaves alternate, simple, short-petiolate, blades

usually with gland-tipped serrate margins, venation pin-

nate, laminar glands absent. Inflorescences axillary, usu-

ally solitary, mostly bisexual (in Central America), spi-

ciform to racemiform, pedunculate with 1-5 proximal 2

flowers and 2-10 distal $ flowers, a broadly sessile stip-

ule-like bract subtending each flower, <5 flowers usually

pedicellate, 9 flowers sessile or short-pedicellate. Male

flowers with 5 sepals, valvate or imbricate in bud, petals

5, free, often unequal, disk absent; stamens 10 in 2 su-

perposed whorls of 5, filaments united near the base into

a column, free distally, anthers dehiscing longitudinally;

pistillode present at the apex of the staminal column,

minute, cylindrical or 3-lobed. Female flowers with 4-7

unequal sepals (often 3 larger alternating with 3 smaller),

united near the base, enlarging in fruit, petals narrow or

reduced and sepal-like, staminodes and disk absent; ova-

ry 3-locular, muricate or with broad-based subulate hairs,

styles with 3-7 lobes, ovules 1/locule. Fruits capsular,

3-lobed, echinate to hispid or verrucose over the outer

and distal surfaces, subtended by the persisting perianth,

breaking into 3 2-valved cocci; seeds globose, ecarun-

culate, raphe narrow, surfaces with a fine reticulum form-

ing small areolae (foveolate), endosperm carnose, copi-

ous.

Breynia disticha J. R. & G. Forst., Char. gen. pi.

146, t. 73. 1776. Phyllanthus nivosus Bull, Cat.

9. 1873; W. G. Smith, Fl. Mag. (London) n.s. t.

120. 1874. B. nivosa (W. G. Smith) Small, Bull.

Torrey Bot. Club 37: 516. 1910. B. disticha for-

ma nivosa (Bull) A. R.-Sm., Kew Bull. 35: 498.

1980.

Shrubs 1-2 m tall, branching often zigzag, leafy

branches 0.5-1.5 mm thick, glabrous, lenticellate; stip-

ules 1-2 mm long, triangular-aculeate. Leaves disti-

chous, glabrous, petioles 2-5 mm long, ca. 0.7 mm thick,

without glands; leaf blades 2-6 cm long, 1.5-3.5 cm

wide, broadly ovate-oblong to ovate-orbicular or elliptic-

oblong, apex rounded, base rounded, drying thin-char-

taceous, often variegated in color, 2° veins 2-5/side. In-

florescences of solitary 2 flowers on slender pedicels 4-

A genus of ca. 40 species, mostly American but

with ca. 6 African species. Our species are easily

recognized because of their tendency to grow in

shallow water or wet depressions in open sunny

sites and the distinctive serrate leaves with many

straight parallel 2° veins. Both our species exhibit

extraordinary variation in leaf form, varying from

linear-lanceolate to ovate-elliptic. However, such

variation is rarely seen within an individual plant.

Our species live in the same habitats and overlap

in many morphological characteristics. Neverthe-

less, the characters of the key seem to separate

specimens consistently. There may be hybridiza-

tion between the two species represented in Cen-

tral America.

BURGER & HUFT: FLORA COSTARICENSIS

69

Key to the Species of Caperonia

la. Stems and petioles lacking slender gland-tipped hairs, stems pubescent to subglabrous; stipules

ovate-triangular to triangular; seed surface with areolae 0.08-0. 1 7 mm wide; leaves mostly lanceolate

to linear C. castaneifolia

Ib. Stems and petioles with few to many slender gland-tipped hairs; stipules narrowly triangular to

lanceolate; seed surface with areolae 0.06-0. 1 2 mm wide; leaves ovate to linear-lanceolate

C. palustris

Caperonia castaneifolia (L.) St. Hill., Hist. PI. Re-

marq. Bresil, 245. 1824. Croton castaneifolium

L., S. P. 1004. 1753. Cap. paludosa Klotzsch,

London J. Bot. 2: 51. 1843. Cap. panamensis

Klotzsch in Seemann, Bot. voy. Herald 103.

1853. Cap. panamensis Pax & K. Hoffm., Pflan-

zenreich 63 (4, 147, 7): 424. 1914. Cap. angusta

Blake, J. Wash. Acad. Sci. 14: 288. 1924. Cap.

stenomeres Blake, J. Wash. Acad. Sci. 14: 288.

1924. Figure 10.

Herbs 0.3-0.8 m tall, basal stems sometimes repent,

larger erect stems longitudinally ridged (Equisetum-\ike),

hollow and with transverse septa, leafy stems 1.5-11 mm

thick, with appressed-ascending whitish hairs 0.2-0.5

mm long, glabrescent; stipules 0.7-3 (rarely to 6) mm

long, 0.5-2 mm wide at the base, triangular to narrowly

ovate, usually glabrous except at the tip, not becoming

reflexed. Leaves with petioles 2-22 mm long, 0.5-2 mm

thick, pubescent in early stages; leaf blades 3-12 cm long,

0.7-3(-6) cm wide, linear-lanceolate to ovate-elliptic (in

different plants), usually gradually narrowed to an acute

or acuminate apex, with 9-30 serrations/side, base slightly

rounded to subtrucate, drying membranaceous to char-

taceous, glabrous above and below or sparsely pubescent

on the midvein beneath, 2° veins 6-15/side. Inflores-

cences 2-7 cm long, spiciform, peduncles to 4 cm long,

rachis appressed-hispidulous, bracts 1-2 mm long, 9

flowers 1-3, on pedicels ca. 1 mm long, $ flowers 5-10,

subsessile. Male flowers white, buds ca. 1.3 mm diam.,

sepals 1.5-2 mm long, petals 1.2-2 mm long, 0.5-1 mm

wide, obovate, equal or unequal; anthers 0.3-0.5 mm

long; pistillode 0.4-0.9 mm long, cylindrical. Females

flowers with 5-6 sepals, the 3 larger becoming 3—4.5 mm

long in fruit, smaller sepals 1.2-1.5 mm long, glabrous

or rarely with a few simple or gland-tipped hairs, petals

1 .2-3 mm long. Fruits 4-5 x 5-6 mm, oblate and 3-lobed,

broad-based hairs 0.3-0.5 mm long on distal surfaces,

columclla 1.5-3 mm long; seeds ca. 3 x 2.5 x 2.5 mm,

subglobose, raphe the entire length of the seed and linear,

areolae 0.08-0. 1 7 mm wide, surface often pale colored

and with or without transverse scales.

Plants of the margins of lakes, rivers, areas of

shallow water, and moist depressions, often in open

sunny sites, mostly in the Pacific lowlands, 0-500

m elevation. Probably flowering and fruiting pri-

marily in the wet season (collections seen are from

January-February, July, and October-Novem-

ber). The species ranges from Mexico to Brazil.

Caperonia castaneifolia is recognized by its open

wet lower-elevation habitats, serrate leaves vari-

able in form, and bisexual spikes with unisexual

flowers. It is not possible to distinguish this species

from its local congener without careful review of

pubescence, stipules, and seeds. The use of the

Linnaean epithet to include C. paludosa was dis-

cussed by Webster and Huft (1988).

Caperonia palustris (L.) A St.-Hill., Hist. PI. Re-

marq. Bresil, 245. 1824. Croton palustris L., Sp.

PI. 1004. 1753. Caperonia palustris var. linear-

ifolia Standl. & L. O. Williams, Ceiba 1: 148.

1950. Figure 10.

Herbs 0.2-1.5 m tall, older stems often slightly in-

flated, hollow, leafy stems 0.4-7 mm thick, with few to

many slender gland-tipped hairs 1-2.2 mm long and

shorter (0.3-1 mm) thin sharp-tipped hairs; stipules 2.5-

6 mm long, 0.4-1 mm wide at base, narrowly triangular

to lanceolate, usually becoming reflexed. Leaves with

petioles 2-24 mm long, 0.5-2 mm thick, usually with

gland-tipped hairs to 2.2 mm long; leaf blades 3-1 2(-

21) cm long, 0.8-4(-7) cm wide, linear-lanceolate to nar-

rowly triangular or ovate-elliptic (rarely ovate-oblong),

tapering gradually to the acute apex, margin with 1 2-42

serrations/side, base acute to rounded or subtruncate,

glabrous above, appressed whitish hairs on the veins

beneath, 2° veins 5-17/side, 3° veins subparallel. Inflo-

rescences 1.4-9 cm long, racemiform or spicate, with 1-

4 proximal 9 flowers and several distal <5 flowers, pe-

duncles 6-^45 mm long, often with a few glandular hairs,

rachis hispidulous; bracts acute, 3 flowers short-pedi-

cellate, 2 flowers subsessile. Male flowers white, ca. 1.8

x 2.3 mm at anthesis, sepals 1.5-3 mm long, ca. 2 mm

broad at base, petals 1.5 x 0.6 mm; anthers 0.3-0.5 mm

long; pistillode 0.6-0.8 mm long. Female flowers 2.5 x

3 mm in early stages, sepals 5-9 with 3-6 larger outer

sepals, becoming 3-5 mm long in fruit, triangular, usu-

ally with gland-tipped hairs 1-1.5 mm long, petals 1-2

mm long; style branches 5-7, 0.4-1 mm long. Fruits 3-

5 mm long, 4.5-7 mm wide, oblate and 3-lobed, broad-

based subulate hairs present on the distal surfaces, ca.

0.5 mm long, gland-tipped hairs present or absent on

the subtending sepals; seeds 2.8-3 mm long, ca. 2.5 mm

diam., subglobose to ovoid, areolae 0.06-0. 12 mm broad,

often dark and with pale narrow transverse scale-like

processes.

Plants of the margins of lakes, rivers, areas of

shallow water, and moist depressions, often in open

70

FIELDIANA: BOTANY

sunny sites, mostly in the Pacific lowlands, 0-800

m elevation. Flowering in August-November;

fruiting in June-December. The species ranges

from the southeastern United States to Argentina.

Caperoniapalustris is recognized by its open wet

lower-elevation habitats, variable serrate leaves

often with many parallel 2° veins, and bisexual

spikes with unisexual flowers. It is not possible to

distinguish this species from its local congener

without careful review of pubescence, stipules, and

seeds. The glandular pubescence of stems is the

most consistently useful marker for this species.

Caryodendron Karsten

Trees, dioecious, stems glabrous or with simple hairs;

stipules lateral, caducous. Leaves alternate, petiolate,

laminae simple and entire, subcoriaceous, venation pin-

nate, with 2 flat rounded glands on the adaxial surface

at the base. Male inflorescences terminal or axillary to

distal leaves, solitary, spiciform thyrses with a thick cen-

tral rachis and a few thick alternate branches, spiciform

axes with subsessile groups of 2-5 $ flowers subtended

by broadly sessile bracts; $ flowers with 3 calyx lobes or

parts, ovate, valvate, petals absent, disk central and large,

pulviniform and often pubescent; stamens 4-7, usually

with a central stamen and 1 or 2 whorls of 3 exterior to

the disk, filaments free, inflexed near the apex, anthers

dorsifixed, dehiscence introrse and oblique, thecae un-

equal, connective apiculate; pistillode absent. Female in-

florescences terminal and solitary, with a thick central

unbranched rachis and 0-2 short basal branches, axes

spiciform (racemose), with subsessile flowers subtended

by sessile bracts; 9 flowers with a thick urceolate calyx

with 3 (5-6) short rounded imbricate lobes, petals 3,

broadly imbricate and rounded distally; disk forming a

cup with subentire margin; staminodes absent; ovary

with 3 (2, 4) locules, ovules 1/locule, styles 3, very short,

stigma-like and little differentiated from the ovary. Fruits

capsules, thick-walled with slightly fleshy smooth sur-

faces, breaking into 3 2-valved cocci; seeds more than 1

cm long, ovoid to globose, ecarunculate.

A Neotropical genus of three species, ranging as

far north as western Panama (Webster & Huft,

1988). The terminal few-branched inflorescences

with thick spiciform axes are unusual among our

species of Euphorbiaceae.

Caryodendron angustifolium Standl., Publ. Field

Columb. Mus., Hot. Ser. 4: 217. 1929.

Trees ca. 6 m tall, leafy stems 3-5 mm thick, glabrous,

smooth and yellowish gray; stipules not seen, stipule

scars obscure. Leaves glabrous, petioles 1 2-22(-30) mm

long, 1.5-2.3 mm thick, geniculate at the apex, petioles

without glands but with 2-4 flat rounded glands in the

leaf surface at base of blade adaxially; leaf blades 18-33

cm long, 5-9 cm wide, narrowly elliptic-oblong to nar-

rowly or oblanceolate, apex acuminate with tip to 5 mm

wide and retuse, margins entire and recurved, tapering

gradually to the cuneate base, drying stiffly chartaceous,

drying yellowish gray, 2° veins 5-8/side, 3° veins sub-

parallel. Male inflorescences 9-23 cm long, with a longer

central axis and ca. 2 proximal lateral branches, peduncle

ca. 1 cm long (to first lateral branch), 2.5-4.5 mm thick,

lateral branches 1.2-1.5 mm thick, rachis ca. 2 mm diam.,

minutely puberulent with ascending hairs 0.1-0.2 mm

long, flower clusters 3-5 mm wide, sessile, bracts ca. 2

mm long, triangular and broadly sessile, flowers 3-7,

closely congested, sessile; <5 flower buds ca. 2 mm long,

anthers 0.4—0.5 mm long. Female inflorescences not seen

[the following information from the closely similar C.

orinocensis: ca. 7 cm long, simple and unbranched or

with 1-3 short (15 mm) thick lateral branches near the

base, rachis 3 mm thick, flowers mostly solitary; 9 flowers

with a thick calyx cup ca. 5 mm long and 4 mm diam.,

with short (1 mm) broadly rounded distal lobes, petals

3, broadly rounded and equaling the calyx in length,

glabrous but with ciliolate distal margin; pistil ca. 4 mm

long, ovoid with gradually narrowed apex and minute

(0.5 mm) style branches]. Fruits not seen, probably sim-

ilar to C. orinocensis where subglobose-obovoid and 3.5-

4 cm diam.

Plants of lowland evergreen forest formations

near the Pacific Coast of western Panama. Flow-

ering in July-August (Cooper & Slater 192 F ho-

lotype, us isotype). Known only from Progreso,

Chiriqui, but probably also occurring in the Golfo

Dulce region of Costa Rica.

Caryodendron angustifolium is recognized by its

narrow oblanceolate glabrous leaves to 30 cm long,

unisexual plants with terminal inflorescences hav-

ing few spiciform branches, and sessile flower clus-

ters. The leaf tips usually have a notch at the apex

with a terminal gland-like area, and the glands at

the lamina base are imbedded in the surface. This

species is very similar to some collections placed

under C. orinocensis Karsten of South America.

The type material of C. angustifolium differs from

that species in having stipule scars that are poorly

developed and leaf blades narrowly cuneate at the

base. More material is necessary to assess the pop-

ulation variability in Panama and to contrast this

with a modern interpretation of population vari-

ation in C. orinocensis.

Chamaesyce S. F. Gray

REFERENCES— D. G. Burch, Two new species of

Chamaesyce (Euphorbiaceae), new combinations,

and a key to Caribbean members of the genus.

Ann. Missouri Bot. Gard. 53: 90-99. 1966. A.

Herndon, Notes on Chamaesyce (Euphorbiaceae)

in Florida. Rhodora 95: 352-368. 1993.

BURGER & HUFT: FLORA COSTARICENSIS

71

Herbs or subshrubs, annuals or with woody base, pros-

trate to erect, monoecious (dioecious), stems often red-

dish in color, latex whitish, glabrous or with simple hairs;

stipules united at the base and interpetiolar or separate,

small and often lacerate, usually persisting. Leaves op-

posite, simple, short-petiolate or subsessile, blades usu-

ally somewhat asymmetric at the base and cuneate to

subcordate, margin serrate or entire, venation palmate

or subpalmate, chlorophyll-bearing cells mostly in a

sheath around the veins and veinlets with colorless areas

between. Inflorescences terminal or apparently axillary

(terminal on reduced axillary short-shoots), made up of

1-many cyathia, often in cymose clusters or glomerules.

Cyathium resembling a flower (cf. Euphorbia), the in-

volucre often resembling a calyx cup or calyx tube bear-

ing 5 lobes alternating with 4 (5) sessile glands, the glands

simple or often with broad flat white or red petal-like

appendages. Male flowers few to many within the cy-

athium, each <5 flower represented by a single stipitate

stamen, anthers with 2 divergent thecae. Female flower

solitary in the cyathium, represented by a stipitate naked

pistil (perianth represented by a rim at the apex of the

stipe), ovary 3-locular, ovules 1/locule, styles 3, free or

united near the base, bifid distally. Fruits usually ex-

serted from the calyx-like involucre by elongation of the

stipe, capsules separating into 3 2-valved cocci; seeds

ovoid to oblong, 3- or 4-sided (terete) in cross-section,

surface smooth, ribbed or sculpted, usually ecarunculate,

embryo straight, cotyledons flat, endosperm copious.

A worldwide genus of ca. 250 species, with most

of the species in the American tropics and sub-

tropics. Many plant taxonomists do not accept this

genus, treating it as a subgenus of Euphorbia (see

discussions in Webster & Burch, 1967; Webster,

1994b, p. 129; McVaugh, 1993, p. 210). Both taxa

possess the cyathium, a flower-like structure made

up of a number of reduced <3 flowers and a single

9 flower within a calyx-like involucre or floral cup.

The reduced 6 and 9 flowers consist only of indi-

vidual stamens or an individual pistil; they usually

have no perianth (see the discussion under Eu-

phorbia). Both individual stamens and pistils are

pedicellate, here called stipitate to avoid confu-

sion. The edge of the involucre usually has a space

resulting from the failure of the 5th gland to de-

velop; the 9 stipe (pedicel) often deflects in this

area. As in Euphorbia, the latex of these plants

may be caustic; they are not eaten by livestock or

most insects. The sap is sometimes used medici-

nally (cf. C. bahiensis and C. hind).

Species of Chamaesyce are usually easy to rec-

ognize because of their small opposite distichous

leaves that are clearly asymmetric at the base, stip-

ules usually united between the petiole bases, and

milky sap. Stems and leaves are often marked with

red or purple. The leaves are often held in a single

plane and slightly succulent. In thin leaves viewed

by transmitted light, the minor veins are seen as

free-ending within clear areas of the leaf. The small-

leaved prostrate mat-forming species are usually

called golondrina in Central America, a name that

may also be used for Alternanthera polygonoides

(Amaranthaceae). Chamaesyce species are almost

always plants of open sunny or early secondary

succession sites, often associated with sandy or

gravelly soils.

Key to the Species of Chamaesyce

la. Fruits glabrous (rarely with a few hairs at the base) 2

Ib. Fruits puberulent (only on the edges in C. prostratd) 8

2a. Leaf blades entire or slightly crenate at the apex, not > 16 mm long, blades usually of similar

size on main stems and lateral stems; plants erect or prostrate 3

2b. Leaf blades serrulate along the distal margins, to 35 mm long; blades of the main stem often

noticeably larger than those of lateral stems; plants rarely prostrate [seeds often dark gray

with poorly developed transverse ribs; species appearing very similar] 5

3a. Erect subshrubs to 60 cm tall; leaf blades stiff, ovate-elliptic or elliptic, to 16 mm long

[fruits 1.2-2 mm long; seeds 1.1-1.3 mm long; plants of Caribbean seashores]

C. mesembryanthemifolia

3b. Prostrate herbs; leaf blades not stiff, oblong to suborbicular, to 10(-12) mm long . . 4

4a. Fruits 2-2 .2mm long; seeds 1.2-1.6 mm long, smoothly rounded and with a longitudinal

line (raphe) down the adaxial side; plants of the Caribbean seashore . . C. bombensis

4b. Fruits 1.2-1.7 mm long; seeds 0.8-1.1 mm long, with 3-4 concave sides and lacking a

longitudinal line or ribs; mostly at edge of fresh water lagoons and in wet depressions

C. serpens

5a. (from 2b) Fruits becoming 2-2.6 mm long, ca. 3 mm wide; rarely collected plants of the

sandy Caribbean seashore, 0-5 m elevation . C. bahiensis

72

FIELDIANA: BOTANY

5b. Fruits 1-2 mm long, ca. 2-2.5 mm wide; plants of open weedy sites and also found near

seashores 6

6a. Fruits 0.9-1.3 mm long; columella < 1 mm long; transverse ribs on seeds often poorly

denned, giving a pitted or irregular surface; inflorescences usually with leafless distal nodes;

stipules usually 1-1.5 mm long and conspicuous C. hypericifolia

6b. Fruits 1 .4-2 mm long; columella > 1 mm long; transverse ribs on the sides of the seeds

usually prominent and well denned; inflorescences with narrow reduced leaves at distal

nodes; stipules usually ca. 0.5 mm long and inconspicuous 7

7a. Distal stems glabrous or with narrow lines of hairs along one side; common plants

C. hyssopifolia

7b. Distal stems usually with hairs along one side; uncommon plants C. nutans

8a. (from Ib) Plants with erect or trailing stems to 1.5 m long [internodes 1-6 cm long; leaf blades to

4 cm long; seeds 0.9-1.2 mm long, often with irregular ribs and dark gray in color; 10-1200 m

elevation] C. lasiocarpa

8b. Plants prostrate to procumbent (erect in C. hirtd), rarely > 0.4 m high or 0.5 m long 9

9a. Cyathia in capitate (leafless) glomerules on short or prominent peduncles; larger leaves 1 5-38 mm

long; internodes to 5 cm long [stems branched mainly near the base, leaf blades usually ovate-

elliptic and tapering to the apex; seeds 0.6-0.8 mm long, with transverse ribs; widespread weeds

to 1400 m elevation] C. hirta

9b. Cyathia not in congested pedunculate capitate glomerules, cyathia or glomerules usually subtended

by leaf pairs or reduced leaves; larger leaves 5-18 mm long; internodes on distal stems rarely >

2 cm long 10

lOa. Fruits usually exserted and easily seen on short peduncles or on a stipitate base, not closely

subtended by cyathium and leaves; distal leaf axils and inflorescences not obscured by thin cotton-

like hairs 11

1 Ob. Fruits appearing sessile on the cyathium and closely subtended by subtending leaves, peduncle or

stipe rarely visible without removal of adjacent leaves; distal leaf axils and base of inflorescences

with thin cotton-like whitish hairs 12

1 1 a. Leaves to 1 4(- 1 9) mm long, narrowed at the apex; cyathia in dense glomerules with subtending

leaves only at the base; seeds 0.7-0.9 mm long C. ophthalmica

lib. Leaves to 7 mm long, usually rounded at the apex; cyathia 1-3 on axillary short-shoots and

subtended by reduced leaves; seeds 0.8-1.1 mm long C. prostrata

12a. Fruits not fully exserted from the cyathial involucre, often splitting the involucre at maturity;

petal old appendages small or obscure, equal in size; seeds 0.6-0.7 mm long [0-1200 m elevation]

C. thymifolia

1 2b. Fruits closely subtended by the cyathia and not splitting them at maturity; petaloid appendages

conspicuous and unequal with 2 larger and 2 smaller on each cyathium; seeds 0.7-0.9 mm long

13

1 3a. Petaloid appendages glabrous above and puberulent beneath; seeds gray or pinkish; 0-2000 m and

usually found above 800 m elevation C. densiflora

1 3b. Petaloid appendages glabrous above and beneath; seeds gray to pink or brown; 0-200 m

. C. dioeca

Chamaesyce bahiensis (Klotzsch & Garcke) Du-

gand & Burch, Ann. Missouri Bot. Card. 54:

344. 1967. Anisophyllum bahiense Klotzsch &

Garcke, Monatsber. Konigl. Preuss. Akad. Wiss.

Berlin 1859: 33. 1859. Euphorbia bahiense

(Klotzsch & Garcke) Boiss. in DC., Prodr. 15

(2): 24. 1862.

Herbs to 0.4 m high, decumbent to erect, often many-

branched, annual or perennial, internodes 8-35 mm long,

leafy stems 0.2-2.5 mm thick, glabrous or with thin curved

hairs to 0.3 mm long; stipules 0.2-0.8 mm long, united,

triangular to lacerate. Leaves sometimes dimorphic with

those of the lateral branches considerably smaller than

those on the main stems, petioles 0.5-1.5 mm long, 0.2-

0.5 mm thick, glabrous; leaf blades 6-20(-30) mm long,

4-8.5(-12) mm wide, oblong to elliptic-oblong or ob-

long-obovate, apex obtuse to rounded, margin subentire

to minutely (0. 1 mm) serrulate with up to 20 teeth/side,

base asymmetric with one rounded side and the other

more oblique, drying chartaceous, glabrous above, with

few thin hairs to 0.8 mm long beneath, venation palmate

BURGER & HUFT: FLORA COSTARICENSIS

73

with 3 major veins. Inflorescences terminal, cyathia usu-

ally solitary in dichasia subtended by opposite leaves or

narrow bracts, peduncles 0.3-1 .5 mm long. Cyathia with

involucres ca. 0.8 mm long, 0.6 mm wide at the apex,

obconic or tubular, glabrous, petaloid appendages 0.2 x

0.3 mm or absent, white; ovary ca. 0.5 x 0.4 mm, ob-

long, styles ca. 0.4 mm long. Fruits 2-2.6 mm long, 2-

3 mm wide, ovoid with truncated base and rounded

sides, glabrous; seeds 1 .3-1 .8 mm long, 0.8-1 . 1 mm wide,

oblong to broadly ellipsoid, with 4 rounded corners in

cross-section, transverse ribs 1-3 but not well developed

and sometimes giving an irregular surface, grayish.

Uncommon plants of sandy seashores, 0-5 m

elevation. Probably flowering throughout the year.

The species ranges along the Caribbean and At-

lantic seashore from Nicaragua to southern Brazil.

Chamaesyce bahiensis is recognized by its small

stature, seaside habitat, well-spaced leaves often

differing in size on main and lateral stems, gla-

brous cyathia and fruits, and gray seeds with un-

usual surface. These plants are very similar to C.

hyssopifolia but differ in the slightly larger fruits

and restriction to seaside habitats.

Chamaesyce bombensis (Jacq.) Dugand, Caldasia

10: 190. 1968. Euphorbia bombensis Jacq.,

Enum. pi. syst. 22. 1760. E. ammannioides

H.B.K., Nov. gen. sp. 2: 55. 1817. C. amman-

nioides (H.B.K.) Small, Fl. Southeastern U.S.

709, 1333. 1903. Figure 6.

Herbs, prostrate or decumbent, forming loose mats to

0.8 m diam. (not rooting at nodes), leafy stems 0.3-2.2

mm thick, internodes 5-35 mm long, glabrous, often

reddish; stipules 0.3-1.7 mm long, with a basal trans-

verse ridge and 2-7 linear laciniate segments. Leaves

often clustered distally, petioles 0.5-1.5 mm long, ca.

0.3 mm thick, glabrous; leaf blades 3-10(-12) mm long,

1 .2-5(-6) mm wide, oblong, apex obtuse or rounded and

often with a mucronate tip ca. 0.2 mm long, margin

entire, base slightly subcordate, asymmetric with 1 side

more rounded than the other, drying chartaceous, often

dark in color, glabrous, surface often reticulate, venation

pinnate, 2° veins 3-6/side. Inflorescences terminal, of

solitary cyathia or dichasia of condensed shoots, gla-

brous, peduncles to 1 .5 mm long; cyathia with involucres

1-1.4 mm long, 0.8-1.2 mm wide distally, obconic, gla-

brous, glands suborbicular, petaloid appendages ca. 0.5

mm long or absent, white; ovary 0.5-0.8 mm long, styles

ca. 0.4 mm long, stipe to 2.3 mm long in fruit. Fruits

1.7-2.2 mm long, 2.2-3 mm wide, ovoid-triangular with

truncated base and rounded sides, glabrous, columella

ca. 1.5 mm long; seeds 1.2-1.4(-1.8) mm long, 1-1.3

mm wide, ovoid-subglobose, rounded in cross-section

and 3-angled only near the apex, whitish, smooth with

a longitudinal line (raphe) on the inner face.

Plants of open sunny sites along the Caribbean

seashore, 0-20 m elevation. Probably flowering

throughout the year. The species ranges from Flor-

ida, Cuba, and Mexico through Central America

to northern South America.

Chamaesyce bombensis is recognized by its small

leaves, lack of pubescence, laciniate stipules, and

unusual rounded seeds. This is our only species of

Chamaesyce with seeds having a longitudinal line

(raphe) clearly demarked on a smooth rounded

surface. The thick little leaves with reticulated

(dried) surface and pinnate venation are distinc-

tive.

Chamaesyce densiflora (Klotzsch & Garcke)

Millsp., Publ. Field Columb. Mus. Nat. Hist.,

Bot. Ser. 2: 391. 1914. Anisophyllum densiflo-

rum Klotzsch & Garcke, Monatsber. Konigl.

Preuss. Akad. Wiss. Berlin 1859: 28. 1860. Eu-

phorbia densiflora (Klotzsch & Garcke) Klotzsch

in Peters, Reise Mossamb. 94. 1862. Figure 7.

Herbs to 0.6 m wide, prostrate, decumbent or erect,

much branched, internodes 3-15(-30) mm long, leafy

stems 0.4—2 mm thick, usually densely pubescent with

thin multicellular hairs to 1 mm long, pubescent

throughout, on 1 side, or in 2 longitudinal rows; stipules

subulate, bifid or lacerate, slender teeth l-1.8(-2.5) mm

long. Leaves subsessile or with petioles to 1 mm long,

ca. 0.4 mm thick, glabrous or puberulent; leaf blades

(4-)7-16(-20) mm long, 1.5-6(-9) mm wide, oblong, to

ovate-oblong, apex bluntly obtuse or asymmetrically

rounded, margin serrulate with small (0.1-0.3 mm) ser-

rations to 16/side, base strongly asymmetric with a

rounded subcordate-auriculate side and a slightly round-

ed side, drying chartaceous, subglabrous or puberulent

on both surfaces with thin whitish hairs ca. 0.3 mm long,

venation palmate with 3 major veins, 2° veins obscure.

Inflorescences terminal or apparently axillary (terminal

on axillary short-shoots), 6-12 mm long, cyathia densely

crowded and obscured by leafy bracts, with thin whitish

hairs to 1 mm long; cyathia with involucres ca. 1 mm

long, campanulate, glands suborbicular to reniform, pet-

aloid appendages 0.9-1.5 mm long, 0.7-2 mm wide, of

2 unequal pairs, ovate to reniform, usually reddish (white),

pilose on the lower surface; stamens with anthers 0.3

mm wide; ovary ca. 1 x l mm, densely appressed pu-

berulent, styles ca. 1.5 mm long, united for 0.5 mm, bifid

distally. Fruits 1-1.6 mm long, 0.9-1.2 m wide, ovoid

with truncated base, minutely pilose, columella 0.6-0.7

mm long; seeds 0.6-0.9 mm long, 0.4-0.6 mm wide,

oblong-triangular, 4-angled in cross-section, with 4-5

prominent transverse ribs on each side, pale grayish or

pink.

Common weedy plants of open sunny sites in

both evergreen and deciduous areas, sea level to

2000 m elevation. In Costa Rica the species is

most often found above 800 m elevation. Flow-

ering and fruiting primarily in July-February. The

species ranges from northern Mexico to northern

South America.

74

FIELDIANA: BOTANY

Chamaesyce densiflora is recognized by the usu-

ally prostrate mat-forming habit, small closely set

leaves strongly asymmetric at the base, and cy-

athia densely crowded (and obscure) within hairy

bracts in the small dense inflorescences. The larg-

er, usually red, petaloid appendages of the glands

occur in 2 unequal pairs on the cyathium. This is

one of the species often called golondrina. This

species is closely related to C. dioeca and is very

similar in overall appearance (q.v.).

Chamaesyce dioeca (H.B.K.) Millsp. (as C. dioicd),

Publ. Field Columb. Mus. Nat. Hist., Bot. Ser.

2: 384. 1914. Euphorbia dioeca H.B.K., Nov.

gen. sp. 2: 53. 1817. Figure 6.

Herbs, prostrate or decumbent, with many branches

from the base and often forming flat mats, 15-70 cm

wide, leafy stems 0.3-1 mm thick, internodes 2-18 mm

long, puberulent with thin hairs 0.2-0.5 mm long; stip-

ules 0.5-2 mm long, with 2-5 linear teeth. Leaves often

marked with red, petioles 0.5-1 .5 long, 0.2-0.4 mm thick,

glabrous or puberulent; leaf blades 3-15 mm long, 1.5-

7 mm wide, broadly oblong to ovate-oblong or obovate-

oblong, apex rounded to obtuse or acute, margin serrate

with 3-6 teeth/side, base strongly asymmetric with a

rounded to auriculate side and a cuneate or slightly

rounded side, drying stiffly chartaceous, green or with

purple spots, glabrous or sparsely puberulent, venation

subpalmate with 3 major veins. Inflorescences terminal

(often on axillary short-shoots) and tightly congested

within the distal leaves, white pubescent at the base,

peduncles short and rarely visible; cyathia with invo-

lucres 0.8-1.2 long, ca. 0.7 mm diam., obconic, ap-

pressed-puberulent, glands reniform to narrowly elliptic,

petaloid appendages of 2 unequal pairs, reddish to white,

glabrous on both sides, the larger 1-1.5 mm long, 1.3-

2 mm wide; ovary ca. 0.7 mm long, styles 0.8-1 mm

long, united for ca. 0.5 mm. Fruits 1-1.4 mm long, 1-

1.3 mm wide, ovoid with truncated base, puberulent,

columella 0.8-1 mm long; seeds 0.6-0.9 mm long, 0.3-

0.5 mm wide, oblong with narrowed tip, 4-sided in cross-

section, often with (2-)3-5 transverse ribs separated by

pits, pinkish or brown.

Common plants of open sunny sites in the Pa-

cific lowlands and along the seashore, 0-600 m

elevation (rarely to 1 200 m elevation elsewhere).

Probably flowering mostly in the wet season (June-

October). The species ranges from central Mexico

to South America.

Chamaesyce dioeca (also labeled dioicd) is rec-

ognized by its usually prostrate habit, puberulent

stems, stipules with two to five slender teeth, very

small leaves, densely congested inflorescences with

thin white hairs, subsessile puberulent fruits, and

restriction to the Pacific lowlands. The cyathia are

noteworthy in having conspicuous petaloid ap-

pendages in two pairs differing in size. These ap-

pendages are glabrous on both surfaces in contrast

to those of the closely related C. densiflora where

the appendages are puberulent beneath. Compare

also the very similar C. thymifolia; see the dis-

cussion by McVaugh (1993, pp. 214-216). We at-

tempt to maintain a traditional usage and are not

convinced that small differences in ribbing of the

lateral seed surfaces is significant.

Chamaesyce hirta (L.) Millsp., Publ. Field Co-

lumb. Mus., Bot. Ser. 2: 303. 1909. Euphorbia

hirta L., Sp. PI. 454. 1 753. E. globulifera H.B.K.,

Nov. gen. sp. 2: 56. 1817. Figure 7.

Herbs 0.1-0.4 m tall, decumbent or erect, internodes

0.5-5 cm long, leafy stems 0.4-2.5 mm thick, minutely

(0.1 mm) puberulent to densely hirtellous with multi-

cellular hairs to 1.5 mm long; stipules united for ca. 0.5

mm at the base and with lobes or teeth 1-2 mm long.

Leaves often marked with red, petioles 1 .2-3.5 mm long,

0.3-0.7 mm thick, puberulent; leaf blades (4-)7-35(-50)

mm long, (3-)4-14(-18) mm wide, ovate-rhombic to

ovate-elliptic or asymmetrically lanceolate, apex acute

to bluntly acute, margin subserrate or serrate with 6-30

teeth/side, 0.1-0.3 mm high, base usually asymmetric

with a cuneatd side and opposing rounded-truncate side,

drying chartaceous, slightly rough or scabrous above with

stiff hairs 0. 1-0.2 mm long, with longer (to 0.9 mm) thin

hairs beneath, venation palmate with 3 (4) major veins,

asymmetric, 2° veins 1-3/side of the midvein. Inflores-

cences usually axillary, solitary and I/node, 4-18 mm

long, 5-16 mm wide, peduncle 2-9 mm long, 0.4-0.5

mm thick, puberulent, bifid distally, pedicels ca. 0.5 mm

long; cyathia with involucres ca. 1 x 0.8 mm, obconic,

glabrous to strigose, often reddish, glands minute, or-

bicular, petaloid appendages usually absent; anthers ca.

0.1 x 0.2 mm. Fruits 0.7-1. 2 mm long, 1-1.4 mm wide,

ovate with truncated base, strigose, persisting styles 0.2-

0.4 mm long, borne on a stipe 0.5-1 mm long, columella

0.7-0.8 mm long; seeds 0.6-0.8 mm long, 0.4-0.5 mm

wide, narrowly ovoid, 4-sided in cross-section, with 4-

5 transverse ribs on each side, grayish to reddish brown

or tan.

Common weedy plants of open sunny sites in

both wet evergreen and seasonally dry deciduous

formations, 0-1400 m elevation. Probably flow-

ering and fruiting throughout the year (but not

collected in September-October). This species, now

a pantropical weed, ranges from the southern

United States to Argentina and the West Indies;

it has been collected on Cocos Island.

Chamaescyce hirta is recognized by its longer

multicellular hairs, leaves usually acute at the apex,

compact pedunculate inflorescences (usually ax-

illary and one per node), and puberulent fruits.

The peduncles are often short and difficult to see.

These plants are often called golondrina in Costa

Rica. It has been reported that C. hirta can cause

BURGER & HUFT: FLORA COSTARICENSIS

75

ulcerations by the transfer of flagellates, but this

is doubtful since the sap is often used to heal

wounds (Standley & Steyermark, 1949, p. 105).

sopifolia L., Syst. Nat. ed. 10, 1048. 1759. E.

brasiliensis Lam., Encyc. Meth. Bot. 2: 423. 1 788.

Figure 7.

Chamaesyce hypericifolia (L.) Millsp., Publ. Field

Columb. Mus., Bot. Ser. 2: 302. 1909. Euphor-

bia hypericifolia L., Sp. PI. 454. 1753. C. glomi-

fera Millsp., Publ. Field Columb. Mus., Bot. Ser.

2: 377. 1913. E. glomifera (Millsp.) Wheeler,

Contr. Gray Herb. 127: 78. 1939.

Herbs 0.2-0.8 m high, prostrate or erect, usually few-

branched with internodes 1-7 cm long, reddish or green,

leafy stems 0.3-2.7 mm thick, glabrous or with few mi-

nute (0. 1-0.3 mm) thin hairs; stipules 0.5-1.5 mm long,

united and triangular or divided; leaf blades (5-)8-38

mm long, (2-)3-16 mm wide, oblong to ovate-oblong or

narrowly oblong, apex bluntly obtuse or rounded, margin

slightly serrate with 7-15 teeth/side, base asymmetric

with a slightly rounded-cuneate side and rounded-trun-

cate side (rarely subcordate), drying membranaceous,

glabrous, venation palmate with 3 major veins, slightly

asymmetric, 2° veins 1-3/side of the midvein. Inflores-

cences axillary or terminal, borne on monopodial or di-

chotomous branches with nodes usually lacking reduced

leaves, cyathia often crowded in short (6 mm) groups,

glabrous; cyathia with involucres ca. 0.8 mm long, ob-

conic, glands elliptic to suborbicular, petaloid append-

ages white to pink (or absent); ovary glabrous, green,

styles 0.3-0.4 mm long. Fruits 0.9-1.3 mm long, ca. 1.5

mm wide, ovoid with truncated base, glabrous, borne

on a stipe 0.5-1 mm long, persisting styles 0.4-0.7 mm

long, columella 0.7-0.9 mm long; seeds 0.8-1 mm long,

ca. 0.6 mm wide, ovoid, 4-sided in cross-section, with

irregular depressions on the surfaces, dark gray to brown

or yellowish.

Plants of open sunny sites in both evergreen and

deciduous vegetation, 0-500 m elevation. This

species is rarely collected in southern Central

America. Probably flowering and fruiting through-

out the year. This species ranges from the southern

United States, West Indies, and Mexico to Argen-

tina and is an adventive in the Old World.

Chamaesyce hypericifolia is recognized by its

usually glabrous parts, usually oblong subsessile

leaves separated by conspicuous internodes, irreg-

ularly arranged distal cyathia lacking reduced leaves

distally, the small fruits, and small seeds with ir-

regular depressions on the surfaces. The distinc-

tions between this species and C. hyssopifolia are

subtle; fruiting material is necessary to distinguish

them. Much Central American material deter-

mined as this species is actually C. hyssopifolia

(q.v.).

Chamaesyce hyssopifolia (L.) Small, Bull. New

York Bot. Gard. 3: 429. 1905. Euphorbia hys-

Herbs 0.3-0.6(-1) m tall, spreading or erect, inter-

nodes of the main sterns 1-3 cm long, leafy stems 0.2-

3.5 mm thick, glabrous or with few minute (0.1 -0.3 mm)

thin whitish hairs along longitudinal lines, terete; stipules

0.3-1 mm long, triangular, divided or with an erose mar-

gin. Leaves with petioles 0.4-3 mm long, 0.1-0.4 mm

thick, glabrous or with a few thin whitish hairs to 0.3

mm long; leaf blades 6-28(-35) mm long, 3-10(-l 6) mm

wide, oblong to elliptic-oblong or oblong-obovate, apex

bluntly obtuse or rounded, margin subentire or minutely

(0.1-0.2 mm) serrate with 6-20 teeth/side, base usually

asymmetric with a cuneate (slightly rounded) side and

an opposite more rounded or truncated side, drying

membranaceous or thinly chartaceous, glabrous, vena-

tion palmate and slightly asymmetric, with 3 major veins,

2° veins 3-5/side of the midvein. Inflorescences terminal

or pseudoaxillary, monochasia or dichasia, peduncles

0.5-2 mm long, distal nodes usually subtended by re-

duced narrow leaves; cyathia with involucres 1-2 mm

long, glabrous, glands oblong to reniform, petaloid ap-

pedanges 0. 1-0.3 mm long and 0.3-0.6 mm wide, round-

ed distally, white or pink; anthers ca. 0.1 x 0.4 mm,

ovary 0.5-0.6 mm long, glabrous, styles 0.3-0.6 mm

long, separate to the base. Fruits 1.5-2 mm long, 1.8-2

mm wide, ovoid or ovoid-trigonous with a truncated

base, glabrous, yellowish, columella 1.1-1.5 mm long,

widened at the apex; seeds 0.8-1.3 mm long, 0.6-0.7

mm wide, oblong or ovoid, 3- or 4-sided in cross-section,

grayish, with 2-4 prominent transverse ribs or obscurely

pitted, gray to black.

Common plants of open sunny sites in evergreen

or deciduous forest areas, 0-1100 m elevation.

Flowering and fruiting throughout the year (prob-

ably primarily in the wet season in deciduous for-

mations). These plants are most often found below

300 m elevation in Costa Rica. This species ranges

from the southern United States and West Indies

to Argentina; it has become naturalized in the Old

World tropics.

Chamaesyce hyssopifolia is recognized by its

stems with longer internodes, oblong usually gla-

brous leaves with palmate venation, glabrous ova-

ries and fruits, and grayish ribbed fruits. The in-

florescences usually bear narrow reduced leaves at

most distal nodes. Large individuals of this species

may resemble C. lasiocarpa, but that species has

puberulent fruits and consistently erect habit. Cen-

tral American material of C. hyssopifolia has often

been misidentified as C. hypericifolia or the rarely

collected seaside C. bahiensis; compare C. nutans.

These plants have been used as a kidney medicine

in Costa Rica (Stevens 24163).

76

FIELDIANA: BOTANY

Chamaesyce lasiocarpa (Klotzsch) Arthur, Tor-

reya 11: 260. 1911. Euphorbia lasiocarpa

Klotzsch, Nov. Act. Leop. 19, suppl. 1: 414.

1 843. E. hypericifolia L. sensu Wheeler in Contr.

Gray Herb. 127: 73. 1939, and Fieldiana Hot.

24, pt. 6: 105. 1944. Figure 7.

Herbs or subshrubs with woody base and erect or

spreading stems, 0.3-1.5 m tall, internodes 0.6-6 cm

long, leafy stems 0.3-3 mm thick, minutely puberulent

with thin curved hairs 0.1-0.3 mm long, glabrescent,

terete; stipules 0.4-1.5 mm long, acute or erose. Leaves

with petioles 0.7-3 mm long, 0.2-0.4 mm thick, puber-

ulent with thin whitish hairs; leaf blades 7-37 mm long,

2-16 mm wide, oblong, oblong-ovate to ovate-elliptic

or oblong-obovoid, apex bluntly obtuse or rounded

(acute), margin minutely serrate with 6-28 teeth/side,

teeth 0.1-0.3 mm high, base usually asymmetric with a

cuneate side and rounded side, drying thinly chartaceous,

puberulent with thin whitish hairs 0.2-0.6 mm long on

both surfaces (glabrate), venation palmate and asym-

metric with 3 major veins, 2° veins 2-5/side of the mid-

vein. Inflorescences of terminal or axillary cyathia in

short-stalked leafy dichasia, peduncles 0.5-4 mm long;

cyathia with involucres 1.2-2.4 mm long, obconic, ca.

2 mm wide at apex, tomentulose, glands suborbicular,

with 3-4 petaloid gland appendages 0.3-0.7 mm long,

0.5-1.4 mm wide, white turning pink; anthers ca. 0.1-

0.3 mm long, rounded; ovary ca. 0.7 x 0.5 mm, ovoid,

densely whitish pubescent, styles 0.5-0.6 mm long. Fruits

1-2.2 mm long, 1-2.2 mm wide, ovoid and 3-lobed,

puberulent, styles 0.5-1 mm long, columella 1-1.3 mm

long; seeds 0.9-1.2 mm long, 0.5-0.7 mm wide, oblong-

ovoid, 4-sided in cross-section, dark reddish brown or

dark grayish, with transverse ribs or with irregular ribs

and a surface with depressions.

Common plants of open sunny sites of season-

ally dry deciduous and partly deciduous vegeta-

tion, 10-1200 m elevation. Probably flowering and

fruiting throughout the year (a majority of collec-

tions were made in July-January). The species

ranges from southern Florida, eastern Mexico, and

the West Indies to Peru and Brazil.

Chamaesyce lasiocarpa is recognized by its usu-

ally erect stems, longer glabrescent internodes, short

pubescence, oblong leaves serrate along most of

their margins, puberulent fruits, and dark grayish

or brown four-angled ribbed seeds. Unlike many

of its congeners, this species is not found along

seashores. Smaller specimens may resemble ma-

terial of C. hyssopifolia (but that species has gla-

brous fruits).

Chamaesyce mesembryanthemifolia (Jacq.) Du-

gand, Phytologia 13: 385. 1966. Euphorbia me-

sembrianthemifolia Jacq., Enum. syst. pi. 22.

1760. E. buxifolia Lam., Encyc. Meth. Bot. 2:

421. 1788. E. litoralis H.B.K., Nov. gen. sp. 2:

54. 1817. E.flexuosus H.B.K., Nov. gen. sp. 2:

55. 1817. C. buxifolia (Lam.) Small, Fl. South-

eastern U.S. 712, 1333. 1903. Figure 7.

Small shrubs or subshrubs 0.2-0.6 m tall, stems erect

or ascending, perennial with woody stems to 8 mm thick,

usually reddish, internodes usually short (3-12 mm) and

uniform on distal stems, leafy stems 0.6-2 mm thick,

glabrous, nodes often thickened; stipules 1-2 mm long,

ca. 1.5 mm broad at the base, triangular to ovate, with

erose margin. Leaves often in 2 ranks, subsessile with

petioles 0.3-0.9 mm long, ca. 0.3 mm thick, glabrous;

leaf blades 5-16 mm long, 3-8 mm wide, elliptic-oblong

to oblong-obovate, apex obtuse or acute, margin entire

and often revolute when dried, base slightly asymmetric

and auriculate on both sides, drying stiffly chartaceous

and gray or yellowish, glabrous, venation palmate with

3 major veins. Inflorescences terminal, of solitary cy-

athia enclosed and hidden by crowded distal leaves. Cy-

athia with involucres 1.3-1.7 mm long, 0.8-1.2 mm

wide at apex, obconic, glabrous, glands elliptic, petaloid

appendages 0.4-0.8 mm long, ca. 0.7 mm wide, obovate,

white, with entire margin; ovary ca. 1 mm long, glabrous,

styles ca. 0.4 mm long, stipe 0.5-1.2 mm long and be-

coming 2.3 mm long in fruit. Fruits 1.7-2 mm long, 2-

2.7 mm wide, broadly ovoid with truncated base to

subglobose, glabrous , columella ca. 1.8 mm long; seeds

1.1-1.3 mm long, 1-1.2 mm thick, ovoid-ellipsoid with

rounded surfaces, the 4 longitudinal edges not well de-

veloped except at the apex, surfaces smooth or slightly

pitted, pale grayish.

Uncommon plants of sandy dunes and ocean

shores of the Caribbean, 0-20 m elevation. This

species has not been collected in Costa Rica but

is known from nearby Nicaragua and Panama.

The species ranges around the shores of the Ca-

ribbean from eastern Mexico, Florida, and the West

Indies to northern South America.

Chamaesyce mesembryanthemifolia is recog-

nized by its short shrubby habit, restriction to Ca-

ribbean seaside habitats, stiff short petiolate entire

leaves often borne in two distichous ranks along

the stems, conspicuous "petals," and unusual seeds.

The seeds differ from most of our species in their

form and smooth surface.

Chamaesyce nutans (Lag.) Small, Fl. Southeastern

U.S. 712, 1333. 1903. Euphorbia nutans Lag.,

Gen. sp. pi. 17. 1816. Figure 7.

Herbs or herbaceous subshrubs to 0.6 m tall, leafy

stems 0.4-2 mm thick, internodes 4-20 mm long, gla-

brous or minutely (0.1 mm) puberulent along 1 side;

stipules 0.3-1 mm long, triangular to rounded-erose or

ciliate, translucent. Leaves subsessile, petioles 0.4-1.3

mm long, 0.2-0.4 mm thick, glabrous; leaf blades 5-22(-

30) mm long, 3-9(-15) mm wide, broadly oblong to

BURGER & HUFT: FLORA COSTARICENSIS

77

narrowly oblong or ovate-oblong, apex obtuse, distal

margin with 5-20 minute teeth, base asymmetric with

2 rounded sides, drying thin-chartaceous, glabrous or

sparsely puberulent beneath, venation palmate with 3

major veins. Inflorescences usually terminal, solitary at

a branch dichotomy or subtended by narrow leaves ca.

6x2 mm, glabrous; cyathia 0.5-1 mm long, 0.5-0.7

mm wide at apex, obconic or tubular, glabrous, glands

elliptic, petaloid appendages present or absent, white to

pink; ovary ca. 0.8 x 0.7 mm, styles 0.4-0.5 mm long.

Fruits ( 1 .3-) 1 .9-2 mm long, ( 1 .4-)2-2.5 mm wide, ovoid-

triangular with rounded sides, glabrous, borne on stipes

to 2 mm long, columella 1.1-1.4 mm long; seeds 1-1.3

mm long, 0.6-1 mm wide, ovoid with narrowed apex,

rounded with 3 or 4 sides in cross-section, transverse

ribs irregular and giving a wrinkled or pitted surface,

dark.

Uncommon plants of open sunny sites in both

evergreen and deciduous forest areas, 0-500 m

elevation. Probably flowering throughout the year.

It is rarely collected in Costa Rica. The species

ranges from southern Canada, the eastern United

States, and Mexico to Costa Rica.

Chamaesyce nutans is recognized by its erect or

decumbent stems (often puberulent along one side),

mostly glabrous parts, larger leaves on main stems,

and dark seeds with irregular (apparently pitted)

surfaces. The senior author believes that Central

American specimens placed here are not specifi-

cally distinct from those identified as C. hyssopi-

folia and that C. nutans may not be worthy of

specific rank.

Chamaesyce ophthalmica (Pers.) Burch, Ann. Mis-

souri Bot. Gard. 53: 98. 1966. Euphorbia

ophthalmica Pers., Syn. PI. 2: 13. 1807. E. pro-

cumbens DC., Cat. PL Hort. Monsp. 111. 1813.

Figure 6.

Herbs, prostrate or decumbent, stems 5-50 cm long,

leafy stems 0.3-1 .8 mm thick, internodes 5-20 mm long,

puberulent with thin straight or crooked hairs 0.2-0.8

mm long; stipules 0.3-2 mm long, laciniate or with 2

linear lobes, puberulent. Leaves with petioles 0.7-2 mm

long, 0.2-0.3 mm thick, puberulent; leaf blades 3.5-14(-

19) mm long, 2-8(-12) mm wide, ovate-elliptic to nar-

rowly ovate-oblong or oblong, apex obtuse to bluntly

acute, margin serrate with 6-18 teeth/side, 0.1-0.3 mm

high and most prominent distally, base strongly asym-

metric with a rounded side and a cuneate side, drying

membranaceous, glabrous or sparsely to densely puber-

ulent with hairs 0. 1-0.5 mm long, venation palmate with

3 major veins. Inflorescences terminal, to 5 mm long,

of congested cyathia and distal leaves, peduncles ca. 0.5

mm long; cyathia puberulent, glands suborbicular, pet-

aloid appendages usually absent; ovary borne on a short

(0.5 mm) stipe, styles ca. 0.2 mm long. Fruits 1.1-1.4

mm long, 1-1.3 mm wide, ovoid-triangular with trun-

cated base and slightly rounded sides, surfaces puberu-

lent with minute (0. 1 mm) whitish hairs, columella 0.8-

1 mm long; seeds 0.7-0.9 mm long, 0.3-0.4 mm wide,

oblong with narrowed apex, 4-sided in cross-section,

concave or with 2-5 transverse ribs on each side, pale

brown to grayish brown.

Uncommon plants of open sunny sites in sandy

river margins and weedy sites, 20-1200 m ele-

vation. Probably capable of flowering throughout

the year. Known in Costa Rica from a single col-

lection made in the city of San Jose in April (Lies-

ner 14176). The species ranges from southern

Florida and the West Indies to Argentina and oc-

curs in the Old World tropics.

Chamaesyce ophthalmica is recognized by its

congested inflorescences, very short styles, and pu-

berulent fruit.

Chamaesyce prostrata (Aiton) Small, Fl. South-

eastern U.S. 713, 1333. 1903. Euphorbia pros-

trata Aiton, Hort. kew. 2: 139. 1789. Figure 6.

Herbs 5-20(-30) cm long, prostrate or scandent, in-

ternodes 1-10 mm long, leafy stems 0.3-1 mm thick,

glabrous or minutely puberulent with thin hairs 0.1-0.4

mm long, often in 2 longitudinal lines; stipules 0.2-0.5

mm long, erose or 2-lobed, puberulent. Leaves with pet-

ioles 0.3-0.9 mm long, ca. 0.2 mm thick, glabrous or

puberulent; leaf blades 2-9 mm long, 1-5 mm wide,

oblong to oblong-obovate or oblong-ovate, apex round-

ed or bluntly obtuse, margin minutely denticulate dis-

tally with 3-9 minute teeth/side, base slightly asym-

metric with larger rounded side and a shorter somewhat

cuneate side, drying chartaceous, glabrous, venation pal-

mate with 3 major veins. Inflorescences axillary or ter-

minal on small axillary short-shoots with reduced (2

mm) leaves, 2-8 mm long, cyathia 1-3, peduncles 0.5-

2 mm long, to 2.3 mm in fruit; cyathia with involucres

0.6-0.9 mm long, 0.4-0.6 mm wide at the apex, obconic,

glabrous or sparsely puberulent, glands suborbicular,

petaloid appendages 4, very small, as wide as the glands.

Fruits 1-1.5 mm long, 1.2-1.4 mm wide, ovoid with

truncated base, often with hairs along the 3 longitudinal

edges and glabrous on the flattened surfaces, borne on a

stipe 0.7-1. 7 mm long, columella 0.9-1. 3 mm long; seeds

0.8-1.1 mm long, 0.4-0.5 mm wide, ovoid-oblong,

sharply tetragonous in cross-section, gray, tan, or pink-

ish, sulcate or with 4-6 narrow transverse ribs on each

side.

Plants of open sunny sites, 0-1200 m elevation.

Probably flowering throughout the year in Central

America. (In Costa Rica, collected only in March-

April, in and near San Jose.) The species ranges

from the southern United States (Texas-Florida),

Mexico, and the West Indies to northern South

America.

Chamaesyce prostrata is recognized by its usu-

ally small prostrate habit, very small leaves, most-

ly glabrous little inflorescences, capsules often with

78

FIELDIANA: BOTANY

thin hairs along the edges, and seeds with well-

defined transverse ribs.

Chamaesyce serpens (H.B.K.) Small, Fl. South-

eastern U.S. 709, 1333. \9Q3.Euphorbiaserpens

H.B.K., Nov. gen. sp. 2: 52. 1817. Figure 6.

Herbs to 30 cm wide, prostrate, much branched, often

rooting at the nodes, leafy stems 0.2-1.3 mm thick, gla-

brous or minutely puberulent with thin hairs to 0.5 mm

long; stipules 0.3-1 mm long, mostly triangular with

lacerate margins, occasionally with 2 rounded glands at

the base, often white. Leaves with petioles 0.5-1.5 mm

long, 0.2-0.3 mm thick, glabrous; leaf blades 1.5-7 mm

long, 0.7-4.5 mm wide, ovate-oblong to oblong or ovate-

orbicular, apex bluntly obtuse or rounded and emargin-

ate, margin entire or subserrate, base slightly asymmetric

with 1 side distally rounded or subcordate and the other

side less so, drying chartaceous, glabrous, venation pal-

mate or subpalmate, usually obscure. Inflorescences ter-

minal or becoming pseudoaxillary, usually of solitary (2)

cyathia borne on peduncles 0.3-1.2 mm long, to 2.3 mm

long in fruit, bracts glabrous; cyathia with involucres

0.8-1 .3 mm long, 0.5-1 . 1 mm wide, obconic, with small

deltoid lobes, petaloid appendages ca. 0.3 mm long, 0.4-

0.5 mm wide, transversely oblong, white. Fruits 1.2-1.7

mm long, 1.3-1.7 mm wide, ovoid with truncated base

and somewhat flattened sides, glabrous, borne on a stipe

0.4-1 .3 mm long, columella 0.8-1 .3 mm long; seeds 0.8-

1 . 1 mm long, 0.4-0.6 mm wide, with 4 rounded corners

in cross-section, sides somewhat concave, transverse ribs

absent or poorly developed, pale brown.

Plants of open sunny areas along margins of

freshwater lakes, lagoons, and dried depressions;

0-200 m elevation. Probably flowering and fruit-

ing throughout the year (collected in Costa Rica

in April and July). In Costa Rica, this species has

only been collected near the mouth of the Rio

Tempisque, Guanacaste Province. The species now

ranges widely, from the midwestern United States

and southernmost Canada to Peru and the West

Indies.

Chamaesyce serpens is recognized by its pros-

trate habit, minute closely set leaves, generally gla-

brous parts, and seeds lacking well-developed

transverse ribs.

Chamaesyce thymifolia (L.) Millsp., Publ. Field

Columb. Mus., Bot. Ser. 2: 413. 1915. Euphor-

bia thymifolia L., Sp. PI. 454. 1953. Figure 6.

Herbs, usually prostrate and forming small mats to

40(-60) cm wide, stems often reddish, internodes 1.5-

12 mm long (less often to 20 mm), leafy stems 0.5-1.7

mm thick, with thin whitish hairs 0. 1-0.5 mm long, often

glabrous on the lower surface or with longitudinal lines

of hairs; stipules 0.5-1.8 mm long, united at the base,

triangular or with linear teeth. Leaves with petioles 0.4-

1 mm long, 0.2-0.4 mm thick, puberulent or glabrous,

drying reddish; leaf blades 3-8(-10) mm long, l-4(-5)

mm wide, oblong to ovate-oblong or ovate-elliptic, apex

bluntly obtuse to rounded, margin subserrate or with 3-

7 teeth/side 0.1-0.2 mm high, base asymmetric with a

straight cuneate side and a rounded truncate or subcor-

date side, drying stiffly chartaceous, glabrous above, gla-

brous or sparsely puberulent beneath, venation subpal-

mate with a midvein and 2 (3) major laterals from the

base, 2° veins 1-3/side of the midvein, usually obscure.

Inflorescences usually axillary and inconspicuous, 2-6

mm long, cyathia 1-3 and congested on short (1 mm)

peduncles, bracts minute; cyathia with involucres 0.8-1

mm long, 0.6-0.8 mm wide, obconic, glands 0. 1-0.2 mm

wide, elliptic to suborbicular, petaloid appendages in 2

unequal pairs or absent, reddish; anthers ca. 0.3 mm

wide, with 2 rounded thecae; ovary ca. 0.7 mm long with

styles 0.3 mm long. Fruits 1-1.3 mm long, 0.9-1.2 mm

wide, ovoid-oblong or ovoid with truncated base, usually

with minute appressed hairs, often with 3 somewhat

flattened sides, closely subtended by the calyx-like cy-

athium (without a developed stipe and splitting the cy-

athium at maturity), columella 0.7-0.9 mm long, slen-

der; seeds 0.6-0.9 mm long, 0.3-0.4 mm wide, 4-sided

in cross-section, with 3-4 prominent transverse ribs on

each side, pale brown.

Common plants of open sunny sites in both ev-

ergreen and seasonally deciduous areas, 0-600(-

1 200) m elevation. Probably flowering and fruiting

throughout the year (collected mostly in Decem-

ber-August). This species is often encountered near

the seashore and in open disturbed sites such as

river edges and roadsides. The species ranges widely

throughout the tropics and subtropics of the

Americas and the Old World.

Chamaesyce thymifolia is recognized by its usu-

ally prostrate mat-forming habit, usually closely

spaced little leaves, small axillary inflorescences

with few cyathia, and puberulent fruits lacking

stipes. It is often called golondrina in Central

America.

Cleidion Blume

Trees or shrubs, monoecious or dioecious, glabrous

or puberulent with simple hairs; stipules present, free,

caducous. Leaves alternate, simple, margins usually den-

tate, venation pinnate, often with 2-many glands or glan-

dular hairs at the base of the blade, domatia of tufted

hairs present or absent. Inflorescences axillary, usually

I/node, unisexual, spicate (<3) or thyrsoid to racemiform

(2), bracts eglandular, flowers small and pedicellate. Male

flowers with united calyx splitting at anthesis into 3—4

valvate lobes, petals and disk absent; stamens 30-80,

densely crowded on a convex receptacle, filaments short

and free, in several vertical series, anthers 4-thecous,

connective usually expanded distally into an appendage

or gland; pistillode absent. Female flowers with 3-6 im-

bricate calyx lobes, petals absent, disk and staminodes

absent; ovary 3- (2-)locular, ovules 1 /locule, styles united

BURGER & HUFT: FLORA COSTARICENSIS

79

only at the base, each style deeply divided and bifid to

2-parted (= 6 long style branches). Fruits capsules break-

ing into 3 (2, 1) 2-valved cocci, columella slender; seeds

subglobose and smooth, ecarunculate, endosperm pres-

ent, cotyledons broad, thin.

A pan tropical genus of about 25 species, with a

majority of species in Australasia, several species

in South America, and a single species in western

Africa. One species ranges northward to Mexico,

while Cleidion membranaceum Pax & K. Hoffm.

(= C. woodsonianum Croizat) reaches central and

eastern Panama.

Cleidion castaneifolium Mull. Arg., Linnaea 34:

184. 1865. Alchornea oblongifolia Standl., Car-

negie Inst. Wash. Publ. 46 1 (Botany of the Maya

Area 4): 66. 1935. C. oblongifolium (Standl.)

Croizat, J. Arnold Arbor. 24: 166. 1943. Figure

12.

Shrubs or small trees 3-12 m tall, trunks 10-25 cm

diam., dioecious, leafy stems 1.5-5 mm thick, at first

minutely (0.1-0.2 mm) puberulent, soon glabrescent;

stipules 2-4 mm long, 1 mm wide at base, narrowly

triangular, acute, appressed-puberulent, caducous. Leaves

with petioles 14-52 mm long, 0.8-1.8 mm thick, thick-

ened (2-3 mm) at apex and base and often geniculate,

glabrous or minutely (0. 1 mm) puberulent; leaf blades

9-26 cm long, 4.5-12 cm wide, elliptic-oblong, elliptic,

elliptic-ovate or oblong, apex acuminate with narrow tip

7-25 mm long, margin subentire or with 15-18 prom-

inent (0.5-2 mm) glandular teeth/side, base obtuse to

acute, base often with lateral glands along the edge or

with imbedded flat glands, drying thinly to stiffly char-

taceous, glabrous above and below (rarely with domatia,

Grayum et al. 8961), 2° veins 6-10/side, 3° veins some-

times subparallel. Male inflorescences 2.5-13 cm long,

rachis 0.6-0.9 mm thick, glabrous or puberulent, glom-

erules with 2-12 flowers, pedicels 1-4 mm long, 0.1-0.2

mm thick, glabrous; $ flowers glabrous externally, buds

1.5-2 mm diam., globose, androecium 1.5-2 mm wide

at base, hemispheric, filaments 0-0.4 mm long, anthers

closely compressed, 0.3-0.4 mm wide, opening apically.

Female inflorescences 1-4 cm long with 1-4 flowers,

rachis 0.6-1 mm thick, minutely puberulent, bracts 0.4-

1 mm long, subtending solitary pedicellate flowers; 9

flowers with 3 calyx lobes 1-2 mm long, puberulent,

ovary ca. 1.4 x 2 mm, oblate, style branches 3.5-9 mm

long, 0.3-0.5 mm thick, puberulent on the inner face.

Fruits 7-10 mm long, 14-18 mm wide, usually with 3

rounded lobes and flattened distal surface, rounded be-

low, woody walls ca. 0.6 mm thick, columella 6-8 mm

long, widened distally; seeds 7-9 mm diam., subglobose,

smooth and lustrous, dark, or grayish.

Plants of evergreen lowland forest formations,

20-700 m elevation (to 1 700 m in Mexico). Flow-

ering primarily in January-October; fruiting in

January-April. The species ranges from southern

Mexico to Ecuador.

Cleidion castaneifolium is distinguished by its

larger pinnately veined leaves with denticulate

margin and petioles thickened at the base and apex,

spiciform 3 inflorescences with many anthers

forming a dome-shaped androecium, few 9 flowers

usually with six style branches, and flesh-covered

fruits. The thickened base and apex of the petioles

often dry dark. The distribution in Costa Rica is

unusual: the Talamanca valley and the moist for-

ests from Volcan Orosi to Upala on the Caribbean

slope and in the evergreen Pacific lowlands (Res.

Biol. Carara to Osa). These plants may resemble

Sorocea and Trophis of the Moraceae.

Cnidoscolus Pohl

REFERENCE— G. Breckon, Studies in Cnidosco-

lus (Euphorbiaceae) 1 . Jatropha tubulosa, J. lieb-

mannii and allied taxa from Central Mexico. Brit-

toniaSl: 125-148. 1979.

Herbs, shrubs, or small trees, monoecious, stems usu-

ally armed with slender sharp stinging hairs, with whitish

latex; stipules free, small. Leaves alternate, simple, pet-

ioles usually long, with glands at the base of the blade,

with stinging hairs, blades usually palmately lobed with

shallow to deep sinuses, venation palmate (pinnate). In-

florescences terminal or pseudoaxillary, solitary, usually

bisexual with proximal 2 flowers and distal $ flowers,

paniculate (of open dichasia with cymose branching),

bracts and bracteoles small. Male flowers with whitish

petaloid perianth of 1 whorl (calyx) united to form a

distinct tube with 5 distal imbricate lobes, petals absent,

disk annular, extrastaminal; stamens 8-10(-25), outer

filaments free and inner usually connate (or all united);

slender staminodes (= pistillode?) sometimes present at

apex of staminal column. Female flowers with white pet-

aloid perianth (calyx), calyx usually 4-5 parted to near

the base, petals and staminodes absent, disk annular;

ovary 3- (5-)locular, ovule 1/locule, styles 3 (5), free,

bifid to laciniate. Fruits capsules with 3 (5) 2-valved

1 -seeded cocci; seeds carunculate, with much endo-

sperm, embryo straight, cotyledons broad.

An American genus of ca. 50 species with cen-

ters of diversity in Mexico and Brazil. The North

American material was studied by G. Breckon and

annotated in 1974. The genus is easily recognized

because of its stinging hairs. Standley and Stey-

ermark (1 949, p. 59) remark that these may be the

most painful of all the stinging plants in Central

America; compare Urera (Urticaceae), Wigandia

(Hydrophyllaceae), and Loasa and Mentzelia (Lo-

asaceae). The plants are also distinctive because

of their large lobed leaves with deep sinuses, glands

at the apex of long petioles, few-branched stems,

80

FIELDIANA: BOTANY

long-pedunculate dichasia, <3 flowers with corolla-

like calyx tube, 2 flowers with separate corolla-like

perianth parts, and three-lobed capsules covered

with stinging hairs.

Key to the Species of Cnidoscolus

1 a. Glands at the apex of the petiole minutely digitate, sometimes lacking or obscure in drying; herbs

or succulent stemmed subshrubs 0.5-2.5 m tall, stems and leaves with many stinging hairs to 10

mm long; leaves 3-5-lobed, the margins entire or with small (3 mm) dentate lobes; <3 perianth lobes

ca. 2 mm long [seeds 10-12 mm long, ca. 3 m thick; deciduous and partly deciduous formations,

0-300 m elevation] C. urens

Ib. Glands at the apex of the petiole 1-2, flat or rounded; shrubs or small trees 1-7 m tall, stems and

leaves with stinging hairs to 7 mm long; leaves with 3-5 large lobes and the margins with additional

prominent acute to acuminate lobes; <3 perianth lobes ca. 4 mm long 2

2a. Seeds 6-8 mm long, ca. 3.5 mm thick; deciduous or evergreen areas, often planted in hedges, 0-

1 200 m elevation C. aconitifolius

2b. Seeds ca. 12 mm long, 4.5 mm thick; rarely collected in southern Central America . . . C. tubulosus

Cnidoscolus aconitifolius (Miller) I. M. Johnston,

Contr. Gray Herb. 68: 86. 1923. Jatropha acon-

itifolia Miller, Gard. Diet. ec. 8, 1768. Figure 2.

Shrubs or small trees l-4(-7) m tall, leafy stems 5-12

mm diam., glabrous or with slender stinging hairs 0.7-

3 mm long, sometimes with broad-based thorn-like

structures to 8 mm high; stipules ca. 3 x 2 mm, with

digitate margin, caducous. Leaves with petioles 6-30 cm

long, 1.5-9 mm thick, with few or many sharp-tipped

stinging hairs 0.5-6 mm long, hairs simple or with basal

stalk to 3 mm long, flat disk-like glands ca. 1.5 mm wide

at or near the apex; leaf blades 1 1-28 cm long, 14-36

cm wide, usually with 3 or 5 larger distal lobes and 2

smaller basal lobes, apex acuminate or acute, tip 5-20

mm long, margins with similar acute to acuminate lobes,

base broadly to narrowly cordate, drying membrana-

ceous, greenish or brown, with a few scattered sharp hairs

above and below, venation palmate with 3 or 5 (7) prom-

inent palmate veins. Inflorescences 1 1-40 cm long, to

55 cm in fruit, 2-10 cm wide, broadly unbelliform di-

chasia, peduncles 1-35 cm long, 2-5 mm thick, with

stinging hairs 0.3-6 mm long, <5 flowers subsessile, 9 flow-

ers short-pedicellate. Male flowers minutely papillate-

puberulent, perianth white, calyx tube 3-6 mm long,

tubular or funnelform, lobes 2.4-4 mm long, 2.2-3 mm

wide, rounded; anthers 1-1.4 mm long. Female flowers

minutely puberulent or glabrous, calyx lobes 6-1 1 mm

long, 1.5-2.5 mm wide, oblong-obovate, white, decid-

uous and leaving a truncated cup 0.7 mm long, ovary

2-4 mm long, style branches 2-3 mm long, distally di-

vided. Fruits 12-18 mm long, ca. 12 mm wide, oblong,

covered with stinging hairs ca. 3 mm long, columella ca.

7 mm long; seeds 6-8 mm long, 4-5.5 mm wide, 3-3.8

mm thick, caruncle ca. 2 mm wide.

Plants of evergreen or deciduous areas, 0-1200

m elevation. Flowering in April-July. Probably

native to southern Mexico but often found in

hedgerows and gardens and apparently naturalized

in the Guanacaste lowlands. This species now

ranges from Mexico to Peru.

Cnidoscolus aconitifolius is recognized by larger

stature and fewer stinging hairs (compared to C.

urens), larger deeply lobed leaves with prominent

acuminate lobes along the margins, and flat dis-

coid glands above the petiole attachment. The

stinging hairs are often few or absent. The young

shoots and leaves have been used as a cooked

vegetable (Standley, 1937), and the trees are used

as fence posts. Chicasquil is a common name.

Cnidoscolus tubulosus (Mull. Arg.) I. M. Johnston,

Contr. Gray Herb. 68: 86. 1923. Jatropha tub-

ulosa Mull. Arg., Linnaea 34: 212. 1865. J. tub-

ulosa var. quinqueloba Mull. Arg., J. cordifolia

Pax, Pflanzenreich IV. 147: 107. 1910. C. cor-

difolius (Pax) I. M. Johnston, Contr. Gray Herb.

68: 86. 1923.

Shrubs or small trees, 2-7 m tall, trunks to 30-40 cm

diam., leafy stems 4-18 mm thick with sharp stinging

hairs 1.5-7 mm long, articulated at the base, with or

without minute (0.2 mm) thin hairs; stipules ca. 2 mm

long and 2.5 mm wide at the base. Leaves with petioles

8-35 cm long, 1.5-5 mm thick, with slender sharp sting-

ing hairs and often with minute thin hairs, with 1-2

rounded flat sessile glands near the adaxial apex; leaf

blades 1 1-35 cm long, 14-38 cm wide, with 3 prominent

distal lobes separated by wide or narrow sinuses 3-12

cm deep, usually with 2 additional lateral/basal lobes,

apex of the major lobes acuminate, margins with short

(0.5-6 mm) teeth separated by 5-1 5 mm, base shallowly

or deeply cordate, drying thin-chartaceous, greenish or

brown, with scattered thin sharp- tipped hairs 1-3 mm

BURGER & HUFT: FLORA COSTARICENSIS

81

long on both surfaces, venation palmate with 5 major

veins, 2° veins 10-15/side of midvein. Inflorescences

usually bisexual, 6-40(-70) cm long, a compound di-

chasium with multiple dichotomies, peduncles 4.5-46

cm long, 1.5-8 mm thick, with stinging hairs, $ flowers

subsessile in axils of basal dichotomies, $ flowers on

pedicels ca. 1 mm long. Male flowers white, 1 1-15 mm

long, minutely and densely puberulent externally, calyx

tube ca. 6 mm long, 2-3 mm diam., lobes 4-5 mm long,

2-3 mm wide, rounded at apex; anthers 1.5-1.8 mm

long. Female flowers white, 10-15 mm long, perianth

tube 5-6 mm long, ca. 3 mm diam. near base, lobes 5-

6 mm long, persisting; ovary ca. 5 mm long, styles united

for 1.5 mm, style branches ca. 4 mm long, twice bifid.

Fruits 16-18 mm long, with few to many stinging hairs,

oblong; seeds 12-13 mm long, ca. 8 mm wide, 4.5-5

mm thick, elliptic in cross-section, broad surfaces smooth,

notched at the base, caruncle 1-1.5 mm wide.

Plants of partly deciduous and montane forest

formations, 900-1700 m elevation in northern

Central America. Probably flowering primarily in

the wet season, May-November. The species rang-

es from Mexico to Nicaragua and in Peru.

Cnidoscolus tubulosus is recognized by its deeply

lobed and dentate leaves, prominent stinging hairs,

tubular perianth in both $ and 9 flowers, and larger

seeds. We have not seen material of this species

from Costa Rica or Panama. See discussion re-

garding this species in Breckon (1979; cited above).

Cnidoscolus urens (L.) Arthur, Torreya 21: 11.

1921. Jatropha urens L., Sp. PI. 1007. 1753. J.

adenophila Pax & K. Hoffm., Pflanzenreich 63

(IV, 147, VII): 400. 1919. C. adenophilus (Pax

& K. Hoffm.) Pax & K. Hoffm., Naturl. Pflan-

zenfam. ed. 2, 19c: 166. 1931. C. urens ssp.

adenophilus (Pax & K. Hoffm.) Breckon, Ann.

Missouri Bot. Card. 75: 1114. 1988. Figure 2.

Herbs or shrubs 0.5-2.5 m tall, stems usually succu-

lent, leafy stems 3-10 mm thick, with many sharp sting-

ing hairs 6-9 mm long, ca. 0.2 mm thick near base;

stipules ca. 2 x 2 mm, laciniate-dentate, caducous. Leaves

with petioles, 7-18 cm long, 1.5-3.5 mm thick, with

short (0.2-0.3 mm) thin hairs and longer stinging hairs,

glands at apex few to many, digitiform, 0.3-1 mm high

but often obscure when dried; leaf blades 5-1 9 cm long,

6-19 cm wide, with 3 large often obovate distal lobes

and 2 smaller proximal lobes, apex short-acuminate to

acute, margins entire or with short (1-3 mm) broad teeth,

base broadly cordate, drying membranaceous, with short

(0.1-0.3 mm) thin hairs on both surfaces, venation pal-

mate with 5 major veins. Inflorescences 4-16(-22) cm

long, 3-8(-l 2) cm wide, umbelliform dichasia, peduncles

3-12 cm long, 1.6-3.5 mm thick, with short (0.2-0.4

mm) thin hairs and stinging hairs to 4 mm long. Male

flowers to 1 1 mm long, white, minutely puberulent or

sometimes with stinging hairs, calyx tube funnelform or

tubular, 4-7 mm long, 2-3 mm diam., lobes 2-4 mm

long, ca. 1 .8 mm wide; anthers ca. 1 . 1 mm long. Female

flowers white, minutely puberulent or glabrous, 5-6 mm

long, corolla lobes ca. 5 x 1.5 mm, deciduous; ovary ca.

2.5 mm long. Fruits 10-13 mm long, 9-11 mm wide,

green with white stripes, with stinging hairs, walls ca. 0.6

mm thick, columella ca. 8 mm long; seeds 8.5-10.5 mm

long, 3.8-5 mm wide, 2.5-3.2 mm thick, whitish to gray,

black or mottled, caruncle 2.5-3.2 mm wide, base slight-

ly bilobed.

Plants of deciduous or partly deciduous forests,

0-300 m elevation (to 600 m in Guatemala). Flow-

ering in June-January. The species ranges from

eastern Mexico to Argentina.

Cnidoscolus urens is distinguished by its dense

covering of sharp stinging hairs, smaller stature,

lobed leaves with usually unlobed margins, and

seasonally dry open habitats. The glands above

the apex of the petiole are often minutely digitate.

The hairs sting severely, the pain sometimes per-

sisting for many hours (Standley, 1937). This spe-

cies is apparently represented by two distinctive

subspecies in Panama (Breckon in Webster & Huft,

1988; Webster & Burch, 1968). These plants have

been called hierba santa in Costa Rica and chor-

rera, chame, ortiga, and pringamoza in Panama.

Codiaeum Adr. Jussieu

Shrubs or small trees, usually monoecious, glabrous

or with simple hairs; stipules present or absent. Leaves

alternate, simple, petiolate, entire or lobed, usually co-

riaceous, pinnately veined. Inflorescences axillary to dis-

tal leaves, solitary or 2/node, racemose or spike-like with

a long unbranched rachis, unisexual or bisexual with 1-

2 proximal 2 flowers, flowers small, $ bracts with 1 flower,

8 flowers 1-6/bract. Male flowers with 5 (3-6) calyx lobes

or parts, imbricate in bud, petals small or rudimentary,

disk of 5-15 free glands; stamens 15-100, borne on the

elevated receptacle, filaments free, anthers erect; pistil-

lode absent. Female flowers with calyx usually 5-parted,

petals absent, disk cupulate, entire or lobed, staminodes

absent; ovary 3-locular, ovules 1/locule, styles 3, simple

and slender. Fruits capsules, globose or 3-lobed, breaking

into 3 2-valved cocci, columella persisting; seeds carun-

culate, endosperm carnose, cotyledons flat.

A genus of ca. 15 species of Australasia and the

western Pacific islands. One colorful ornamental

species is now widely cultivated throughout the

tropics and subtropics.

Codiaeum variegatum (L.) Adr. Juss., Euphorb.

Gen. Tent. 1 1 1, t. 9, f. 30. 1824. C. variegatum

(L.) Blume, Bijdr. fl. Ned. Ind. 606. 1825. Cro-

ton variegatus L., Sp. PI. ed. 3. 1424. 1764. Fig-

ure 32.

82

FIELDIANA: BOTANY

Shrubs and small few-branched treelets 1-5 m tall,

leafy stems 3-10 mm thick, glabrous or glabrescent; stip-

ules absent. Leaves with petioles 1-4 cm long, glands

absent; leaf blades 5-35 cm long, 1-13 cm wide, shape

extraordinarily variable in different cultivars (also vari-

able on the same plant), usually long and narrow, nar-

rowly obovate to oblanceolate, apex acute to rounded,

margin entire, with or without 1-3 rounded lobes and

sinuses (with a bladeless petiole-like portion in the center

of the blade in some varieties), drying stiffly chartaceous

to subcoriaceous, glabrous, lustrous, variously colored.

Inflorescences 12-40 cm long, usually erect, unisexual,

glabrous, spike-like with 1-3 3 flowers in sessile fascicles

and pedicels 2-4 mm long.

Codiaeum variegatum is native to the south-

western Pacific and is now a favorite ornamental

cultivar because of its brilliantly colored leaves

mottled with dark green, yellow-green, yellow, rose-

red, red, or purple. The blades often have paler

colored areas around the major veins. The blades

vary greatly in shape but are generally long and

narrow and have entire margins. The plants are

often used as hedges but are restricted to lower (0-

900 m) elevations. Laurel, cintillo, and "garden

croton" are common names.

Conceveiba Aublet

Small to large trees, dioecious, minutely stellate-pu-

berulent, glabrescent; stipules paired at the leaf base,

deciduous. Leaves alternate, simple, petioles often ge-

niculate at the apex and thickened at the base (stipels

absent); leaf blades slightly crenate-denticulate with gland-

tipped lobes or sinuses, minutely stellate puberulent be-

neath, venation palmate (in our species) or pinnate. Male

inflorescences terminal or axillary, solitary, simple and

racemose or branched and paniculate, often broad, flow-

ers solitary or in sessile groups along the rachis, bracts

small (glands not apparent), pedicels short; $ flowers with

ovoid or spherical buds, calyx opening irregularly or 3-

4 parted, corolla and disk absent; stamens ca. 1 6-many,

filaments free, anthers dehiscing longitudinally, thecae

rounded; pistillode absent. Female inflorescences ter-

minal, solitary, narrowly spiciform racemes with a thick

rachis and distant solitary flowers subtended by small

broad-based bracts, lateral glands usually present at the

base of the bracts, pedicels short and thick, borne directly

on the rachis (C. latifolia) or on a very short articulated

lateral branch of the rachis (C. pleiostemona); $ flowers

with 5-8 narrow stiff imbricated puberulent sepals (al-

ternating with large glands in C. latifolia), petals and

disk absent, staminodes absent; ovary 3-4 locular, ovules

1/locule, styles united only at base, thick, papillose adax-

ially, bifid distally. Fruits fleshy and large, 3-costate,

separating into 3 2-valved capsules; seeds large, carun-

culate.

A Neotropical genus of seven to nine species;

all are South American, except the Costa Rican

endemic, a recently discovered African species and

an undescribed Panamanian species. The stellate

nature of the pubescence is difficult to see because

of the small size of the hairs. Herbarium material

of our species was previously filed under Vecon-

cibea; compare Alchornea.

Conceveiba pleiostemona J. D. Smith, Hot. Gaz.

54: 243. 1912. Veconcibea pleiostemona (J. D.

Smith) Pax & K. Hoffm. Figure 20.

Trees, 10-30 m tall, 25-100 cm dbh, large trunks

sometimes fluted, leafy twigs 2-8 mm thick, with short

(0.1-0.3 mm) appressed-stellate hairs and with longer

(0.4 mm) straight or V-shaped hairs attached at the mid-

dle; stipules 4-8 mm long, 0.7-1.2 mm wide, linear,

appearing densely sericeous with ascending hairs, decid-

uous. Leaves with petioles 2.2-12 cm long, 1-3 mm

thick, minutely stellate-pubescent, sometimes drying

darker and thinner along the terminal 4-5 mm; leaf blades

5-22 cm long, 4-19 cm wide, broadly ovate to ovate-

suborbicular, apex obtuse to rounded or with a short-

acuminate tip 3-10 mm long, margin bluntly serrulate

with 15-23 teeth/side, teeth 0.3-1 mm high and gland-

tipped, base rounded to subcordate, drying stiffly char-

taceous or subcoriaceous, glabrous or pubescent on the

midvein above, minutely stellate-pubescent beneath, ve-

nation palmate, 2° veins 4-6/side, 3° and 4° veins sub-

parallel and perpendicular to the higher rank veins. Male

inflorescences axillary or terminal, 7-20 cm long, simple

and spicate or compound and paniculate with lateral

branches to 4 cm long, peduncles 2-35 mm long, 0.7-2

mm thick, minutely stellate-puberulent, bracts ca. 1 mm

long, pedicels 0.5-1 mm long, drying black; $ flowers

with spherical buds ca. 2 mm diam., perianth parts 1-

2 mm long, mostly glabrous and drying black; stamens

30-60, filaments 0.5-1.9 mm long (not 7-1 1 mm as in

the original description), anthers 0.4-0.5 mm long. Fe-

male inflorescences terminal, to 22 cm long in fruit, spi-

ciform at first, rachis 2-3 mm thick, minutely stellate-

puberulent, bracts 3-5 mm long, 1-2 mm wide at base,

subtending a short lateral peduncle (becoming up to 10

mm long in fruit), articulated below the short (1-3 mm)

thick ( 1 mm) pedicels; 2 flowers with 5 sepals 3-5 mm

long, 1 mm wide at base; ovary ca. 4.5 mm long, 3-angular

in cross-section, style branches becoming 4-5 mm long

and recurved, 0.5-0.7 mm thick. Fruits ca. 1.8 x 1.2

cm, oblong with elevated longitudinal ridges and per-

sisting style branches, green and fleshy, pedicels red; seeds

ca. 10 x 8 mm, smooth, brown.

Trees of Caribbean rain forest formations on

well-drained soils, 50-600 m elevation. Flowering

in June-July; fruiting in August-October. The spe-

cies is known only from Costa Rica, ranging from

just north of Tortuguero National Park to Amubri

in the Talamanca valley. It probably occurs also

in adjacent Nicaragua and Panama.

Conceveiba pleiostemona is recognized by its

large stature, minute stellate pubescence, broadly

ovate palmately veined leaves with subparallel mi-

BURGER & HUFT: FLORA COSTARICENSIS

83

nor venation, short-pedicellate <5 flowers with many

stamens, and fleshy fruit on long narrow inflores-

cences. The large size of these trees and their re-

stricted flowering and fruiting season probably ac-

count for the paucity of collections. The fruits are

eaten by macaws (Aras ambigua). Compare the

superficially similar Aparisthmium cordatum,

which lacks the stellate hairs and has smaller cap-

sular fruits.

Croton Linnaeus

REFERENCE— G. L. Webster, A provisional syn-

opsis of the sections of the genus Croton (Eu-

phorbiaceae). Taxon 42: 793-823. 1993.

Trees, shrubs or herbs, bisexual (monoecious) or uni-

sexual (dioecious), sap often white or colored, stems with

simple, stellate, scurfy or flat rounded peltate hairs; stip-

ules small or absent, usually caducous. Leaves alternate

or sometimes opposite at congested distal or flowering

nodes, simple, petiolate, often with glands near the apex

of the petiole or at the base of the blade, blades entire

to deeply lobed, margins entire to serrate, venation pal-

mate or pinnate. Inflorescences terminal or axillary, spi-

cate to racemose (actually a condensed thyrse with a

single unbranched rachis, but apparently branched or

pseudopaniculate when distal leaves fail to develop), bi-

sexual or unisexual, with 1-10 usually solitary 9 flowers

at proximal nodes and many <5 flowers distally when

bisexual, rachis usually pubescent, bracts and bracteoles

small, 6 flowers often in sessile fascicles (cymules). Male

flowers with 4—6 valvate or imbricate calyx lobes, petals

usually 5 (4, 6, 0), receptacle usually pilose; stamens 8-

50, filaments inflexed in bud and free, pistillode absent.

Female flowers with 5-7 (4-10) calyx lobes, imbricate

or valvate, petals 0 or 5 and small, staminodes absent,

disc entire or lobed; ovary with 3 (1, 2) locules, ovules

1/locule, styles 3 (2), bifid or several times bifid. Fruits

usually capsules with 3 (2) 2-valved cocci, columella

usually persisting; seeds oblong in outline, rounded abax-

ially, carunculate, endosperm present, embryo with broad

flat cotyledons.

A very large genus of ca. 800 species of tropical

and warm-temperate regions. South America, the

West Indies, and Mexico are important centers of

species diversity. The stellate or lepidote hairs,

narrow unbranched inflorescences, stamens in-

flexed in bud, divided style branches, capsular

fruits, and inapeturate pollen grains help distin-

guish the genus. The glands near the apex of the

petioles of some species can be quite striking, from

sessile and saucer-like to stipitate and patelliform.

Plants of this genus are sometimes conspicuous

because their leaves turn bright yellow or orange

before they are shed.

The Costa Rican species of Croton include both

wide-ranging species and local endemics with re-

markably narrow ranges. Many species are poorly

represented in herbaria, probably because they are

part of open weedy or early secondary vegetation.

A few can become tall trees, and these are not well

collected. Many species display considerable vari-

ation in leaf size, leaf form, pubescence, inflores-

cences, and floral morphology. Such variation can

make the determination of individual specimens

very difficult. The genus is rich in alkaloids, and

a number of species in Asia and South America

have been used medicinally and for teas (cf. C.

niveus). Some authors recognize the species of sec-

tion Julocroton (Mart.) Webster as a genus.

Key to the Species of Croton

la. Young stems or petioles with appressed flat rounded centrally attached (peltate) hairs 0. 1-0.5 mm

diam., sometimes with united radiating rays separated distally and resembling stellate hairs, stellate

hairs present in a few species; stamens 10-1 5/flower 2

Ib. Young stems lacking flat rounded centrally attached hairs, hairs sometimes centrally flattened with

radiating hairs but these not united along their lateral edges to form a broad flat surface, the hairs

stellate to scurfy and rounded, or simple; stamens 8-50/flower 10

2a. Small (< 1 m) shrubs of the Caribbean seashore; leaves not > 4.5 cm long, upper (adaxial)

surfaces of leaves with stellate hairs, young stems and lower (abaxial) surface of leaves with

peltate-stellate hairs; $ flowers apetalous [stipules absent] C. punctatus

2b. Shrubs or trees, not confined to the Caribbean seashore; mature leaves usually > 5 cm long,

upper leaf surfaces glabrous or with flat rounded peltate hairs (stellate hairs also present in

C. pachypodus and C. tonduzii), young stems and lower leaf surfaces with peltate hairs; <5

flowers with petals (but sometimes small) 3

3a. Venation palmate (basal 2° veins reaching the midpoint of the leaf margin or more distally)

4

84

FIELDIANA: BOTANY

3b. Venation pinnate or subpalmate 5

4a. Leaf blades with entire or subentire margin, often silvery beneath with a dense covering

of peltate hairs, 4-14 cm long, broadly ovate-orbicular to triangular; plants often grown

in hedgerows, 0-1800 m elevation; seeds 6-16 mm long C. niveus

4b. Leaf blades with prominently dentate margin, blades not silvery beneath, 9-18 cm

long, ovate to ovate-elliptic or ovate-oblong; plants rare on the evergreen Pacific slope,

400-900 m; seeds 5-6 mm long C. tonduzii

5a. Seeds 20-28 mm long in capsules 3-5 cm long [trees to 30 m tall; leaves to 1 3 cm long, with

2 lateral glands at the apex of the petiole; inflorescences mostly terminal, to 9 cm long; 300-

1000 m] C. pachypodus

5b. Seeds < 10 mm long, capsules to 1.5 cm long 6

6a. Styles much divided with > 20 distal stigmatic branches/flower; leaf blades rounded and

truncate to cordate at the base [8-26 cm long, ovate-oblong; evergreen forests] 7

6b. Styles 2-3 times bifid, rarely with > 1 8 distal stigmatic branches/flower; leaf blades rarely

rounded at the base, never cordate 8

7a. Petioles without lateral glands at the apex, leaf blade rounded and truncated at the

base, secondary veins 9-13 pairs; 6 flowers solitary on the rachis . . C. tenuicaudatus

7b. Petioles with 2 lateral sessile glands at the apex, leaf blade rounded and cordate at base,

secondary veins 11-17 pairs; $ flowers in groups of 5-1 1 C. skutchii

8a. Apex of petiole lacking paired lateral or adaxial glands; wide-ranging and variable trees or

shrubs [on both Pacific and Caribbean slopes, usually found at 0-700 m elevation; 2° veins

8-13/side; styles bifid at base and with ca. 18 distal style branches; seeds 7-8 mm long] . .

C. schiedeanus

8b. Apex of petiole usually with 2 distinct stalked adaxial/lateral glands; restricted species . . 9

9a. Leaves with few to many stellate-scurfy hairs on the upper surface, 2° veins 3-6/side; styles

bifid in the distal half (6 distal branches/flower); seeds 6-7 mm long; known only from the

Cordillera de Tilaran near Monteverde, 1400-1600 m elevation C. mexicanus

9b. Leaves glabrous above, 2° veins 10-22/side; styles 2 times bifid (12 branches); seeds ca. 3.5

mm long; rarely collected trees of the Caribbean slope at 200-800 m .... C. lanjouwensis

lOa. (from Ib) Leaf blades often ovate (ovate-oblong) with the larger leaves usually becoming > 15 cm

long, the base usually rounded and truncate to cordate, sessile or stipitate glands usually present

near the apex of the petiole; pubescence usually of scurfy-stellate hairs; trees and shrubs not found

in dry seasonally deciduous areas 11

1 Ob. Leaf blades not ovate if becoming > 1 3 cm long, the base rounded and truncate to cordate only

in leaves < 1 3 cm long, glands present or absent near the apex of the petiole, pubescence with

various types of stellate or scurfy hairs; trees, shrubs, or herbs of both dry deciduous and wet

evergreen formations 20

1 la. Larger leaves often with 3 distal lobes and broad shallow sinuses (note that smaller leaves

are usually unlobed), venation palmate; 9 calyx lobes 5-16 mm long [rarely collected species]

12

lib. Leaves with a single acute or acuminate apex (rarely with distal lobes), venation palmate to

pinnate; 9 calyx lobes usually < 5 mm long (except in C. jimenezii) 13

12a. Stamens ca. 1 1 /flower; 9 calyx lobes 5-7 mm long, styles much-branched; seeds ca. 5

mm long; leaves, stems, and inflorescences not yellowish white with dense tomentulous

pubescence C. smithianus

12b. Stamens ca. 50/flower; 2 calyx lobes 8-16 mm long, styles 2 times bifid; seeds ca. 7

mm long; leaves, stems and inflorescences with a dense tomentum of yellowish white

hairs C. speciosus

\ 3a. Venation pinnate in larger and smaller leaves, length of leaf blade often twice the width,

often ovate-oblong and truncated at base 14

1 3b. Venation palmate or subpalmate in larger leaves, length of leaf blade usually less than twice

the width, usually ovate and subcordate at the base 17

1 4a. Plants growing at 0-700 m elevation in Costa Rica; glands at the apex of the petiole

BURGER & HUFT: FLORA COSTARICENSIS 85

usually 2, sessile; stamens ca. 14, anthers 1-1.5 mm long; leaf blades often oblong . .

C. billbergianus

14b. Plants at (0) 800-2300 m in Costa Rica; glands at the apex of the petiole 2-7, often

stalked; stamens 14-33, anthers 0.6-0.9 mm long; leaf blades often ovate 15

1 5a. Leaf blades rarely > 1 5 cm long; stellate hairs compact (ca. 0.2 mm diam.) and usually

flat, petiole with 2 lateral stalked glands at apex; stamens 14-16; seeds 6-7 mm long

[Cordillera de Tilaran at 1400-1600 m elevation] C. mexicanus

1 5b. Larger leaf blades usually > 1 5 cm long; stellate hairs often elevated and prominent;

petiole with 2-9 glands at adaxial base of blade; stamens 14-33; seeds 4-5 mm long

16

16a. Calyx lobes of 9 flowers 2.5-9 mm long, oblong; pubescence with many small brownish

scurfy hairs and some stellate hairs [<5 flowers sometimes present with proximal 9 flowers

on bisexual inflorescences; seed ca. 4 x 3 mm; 1000-2500 m, Volcan Barva to San

Isidro] C. jimenezii

1 6b. Calyx lobes of 9 flowers 1 .5-4 mm long, usually triangular; pubescence mostly of whitish

or yellowish hairs, scurfy to stellate 17

1 7a. Seeds 6-8 mm long, surfaces smooth; glands 2 and sessile near the apex of the petiole; stamens

ca. 15; 9 and <5 calyx united ca. 50% and conspicuous; plants restricted to the eastern Meseta

Central and around Cartago, 900-1600 m elevation C. hoffmannii

17b. Seeds 3.5-6 mm long, usually rugulose; glands 2-12 at the apex of the petiole and sessile or

stipitate; stamens 15-33; and without the preceding combination of characters 18

18a. Plants restricted to the Chiriqui Highlands at 1300-2100 m; leaf blades usually less than 14

cm long and cordate [seeds 5-6 mm long; <5 flowers present with the proximal 9 flowers on

bisexual inflorescences, stamens 25— 40/flower] C. pungens

18b. Plants widely distributed and common, 0-2100 m elevation; larger leaf blades more than 15

cm long, cordate or truncate (the following two species are very similar and can be difficult

to separate when bisexual inflorescences are lacking) 19

19a. Male flowers present with proximal 9 flowers on bisexual inflorescences, flowers usually in

glomerules (cymules) along the rachis; 9 flowers pedicellate, & flowers mostly in fascicles along

rachis. stamens 1 3-22/flower; seeds 2.8-5 mm long C. draco

19b. Male flowers not present with proximal 9 flowers on bisexual inflorescences, flowers often

solitary along the rachis; 9 flowers subsessile; <3 flowers usually 1 -few/bract along the rachis,

stamens 18-3 I/flower; seeds 4.8-5.7 mm long C. xalapensis

20a. (from lOb) Leaves with 3 prominent distal lobes separated by deep narrow sinuses, 2 additional

smaller basal lobes often also present [seeds ca. 5 x 3 mm, oblong; herbs to 1.5 m tall in open

sunny sites in seasonally dry lowlands] C. lobatus

20b. Leaves lacking 3 prominent distal lobes and deep sinuses 21

2 la. Plants of seasonally very dry deciduous areas in the Guanacaste lowlands (0-500 m) 22

21b. Plants of evergreen or partly deciduous forest formations, above 500 m elevation in Guanacaste

and in other areas 27

22a. Leaf blades silvery white or bright grayish white beneath; stipules often rounded and leaf-

like in texture; 9 sepals broadly ovate and often laterally reflexed [stamens 15; glands absent

or minute at apex of petiole] C. yucatanensis

22b. Leaf blades not silvery white or bright grayish white beneath, often pale grayish; stipules not

rounded or leaf-like; 9 sepals not broadly ovate 23

23a. Leaf blades not exceeding 3.5 cm in length [glands absent at the apex of the petiole; plants

not exceeding 1 m in height and rarely collected; stamens ca. 11; seeds 4.5-4.8 mm long]

C. ovalifolius

23b. Leaf blades often exceeding 3.5 cm in length 24

24a. Venation pinnate or subpalmate, shrubby plants 25

24b. Venation palmate, herbs or shrubs 27

25a. Glands 2—4 at the apex of the petiole, blades lanceolate to narrowly elliptic or ovate,

with prominent denticulate margin, venation pinnate; commonly collected in many

sites [stamens 1 1 ; seeds 3.5—4 mm long] C. jutiapensis

86 FIELDIANA: BOTANY

25b. Glands absent at the apex of the petiole, blades ovate to ovate-elliptic, ovate-oblong

or ovate-triangular, with subentire margin; uncommon in Costa Rica 26

26a. Venation subpalmate, 2° veins 3-6 pairs, blade not cordate at base, thinly chartaceous;

stamens 1 5; seeds 5-5.5 mm long C. sphaerocarpus

26b. Venation pinnate, 2° veins 5- 1 0 pairs, blade often subcordate at base, stiffly chartaceous;

stamens ca. 1 1 ; seeds not seen C. axillaris

27a. (from 21b and 24b) Plants weak-stemmed weedy annuals, rarely > 1 m tall; wide-ranging species

[stellate hairs with thin rays, not scurfy; stamens 8-12; seeds 3-4 mm long] 28

27a. Plants woody shrubs and trees, 0.3-25 m tall; wide-ranging or locally endemic species 31

28a. Stalked or sessile glands absent at the apex of the petiole, leaf blades drying pale greenish

above and whitish below with a dense to men turn of stellate hairs, blades 2-15 cm long . .

C. argenteus

28b. Stalked or sessile glands usually present at the apex of the petiole, leaf blades drying green

or dark green above, not whitish and densely tomentulose beneath, blades 1-9 cm long . .

29

29a. Leaf blades elliptic-lanceolate to narrowly triangular, conspicuously dentate with teeth 2-5

mm high [hairs on stems to ca. 1 mm long; anthers 0.3-0.4 mm long; evergreen areas 0-800

m elevation] C. trinitatus

29b. Leaf blades ovate to narrowly oblong, with margins crenate or rounded-dentate with teeth

1-3 mm long 30

30a. Glands at apex of petiole stipitate; hairs on stems appearing simple and 1-3 mm long, usually

retrorse; leaf blades broadly ovate to ovate-elliptic; floral bracts with slender gland-tipped

segments [anthers 0.4-0.5 mm long]; deciduous and evergreen areas, 0-1700 m elevation

C. hirtus

30b. Glands at apex of petiole sessile or subsessile; hairs on stems stellate with rays to 1 mm long;

leaf blades narrowly oblong to broadly ovate; floral bracts without glands or gland-tipped

hairs; rarely collected in Central America C. glandulosus

3 la. Small (< 1 m) shrubs found only near the Caribbean seashore; stems and lower (abaxial) surface

of leaves with peltate-stellate hairs [leaves to 4.5 cm long] C. punctatus

3 1 b. Shrubs or trees, usually > 1 m tall and not confined to the Caribbean seashore; peltate hairs absent

or with flat peltate-like hairs in C. mexicanus 32

32a. Largest leaves 6-10 cm long, usually densely pubescent; small shrubs of open sites at 1 100-1600

m elevation around the Meseta Central 33

32b. Largest leaves 8-22 cm long, sparsely to densely pubescent; taller shrubs or trees not collected

around the Meseta Central 34

33a. Calyx lobes of 9 flowers with slender naked gland-tipped hairs 1-2 mm long; petioles lacking

stalked glands at the apex, 2° veins 4-13/side; stamens 15 C. decalobus

33b. Calyx lobes of 2 flowers without slender gland-tipped hairs; petioles with 2 stalked glands at

the apex, 2° veins 3-7/side; stamens 9-1 1 C. ortholobus

34a. Leaf blades membranaceous to thinly chartaceous, up to 22 cm long, usually elliptic to ovate-

lanceolate, hairs of lower leaf surface with fewer than 1 2 slender rays; shrubs or small trees of

evergreen forests 50-800 m elevation 35

34b. Leaf blades stiffly chartaceous, to 16 cm long, usually ovate to ovate-elliptic, hairs of lower leaf

surfaces with 1 3 or more slender rays; trees of lowland rain forests or cloud forests and partly

deciduous forests 36

35a. Leaves alternate or opposite at some nodes, blade margins usually with prominent (3-5 mm)

teeth, stalked yellowish glands often present in the sinuses of the margin, small (0.3 mm)

yellowish glands not usually present on the lower surfaces, blades drying brown or dark green

C. brevipes

35b. Leaves alternate, margins with few small teeth or subentire, margin lacking stalked glands,

small yellowish glands present near vein axils on the lower leaf surface, blades drying blackish

C. sp. A

36a. Leaves without lateral glands at apex of petiole; blades bright whitish tomentose beneath; stellate

BURGER & HUFT: FLORA COSTARICENSIS 87

hairs not peltate or scurfy; deciduous and partly deciduous forests [700-1 100 m elevation; stamens

ca. 1 2; seeds 4-5 mm long] C. sp. aff. yucatanensis

36b. Leaves usually with 2 lateral or adaxial glands at apex of petiole; blades not densely whitish

tomentose beneath; stellate hairs often peltate or stellate-scurfy; evergreen forests 37

37a. Leaf blades mostly ovate-elliptic with fewer than 6 pairs of 2° veins, pubescence of stems and

inflorescences mostly flat-stellate; inflorescences simple; seeds 6-7 mm long; 1300-1500 m ele-

vation C. mexicanus

37b. Leaf blades mostly ovate-lanceolate with more than 8 pairs of 2° veins; pubescence of stems and

inflorescences with thick stellate-scurfy hairs; inflorescences often with 2-4 long branches; seeds

4-5 mm long; 200-800 m elevation C. billbergianus

Croton argenteus L., Sp. PI. 1004. 1753. Julocro-

ton argenteus (L.) Didr., Vidensk. Meddel.

Dansk. Naturhist. Foren. Kobenhavn 1857: 134.

1857. Figure 16.

Annual herbs 0.2-1 m tall, bisexual, leafy stems 0.8-

7.5 mm thick, stellate-pubescent with appressed hairs

0.3-0.5 mm diam. or with long rays to 0.9 mm; stipules

4-1 1 mm long, linear-subulate, simple or divided dis-

tally, with hairs to 1.4 mm long. Leaves often closely

congested beneath the inflorescences (becoming pseu-

doverticellate), petioles 3-105 mm long, 0.7-2 mm thick,

appressed stellate-pubescent, glands absent at apex; leaf

blades 1.8-10(-15) cm long, 1.2-6(-8) cm wide, ovate

to ovate-oblong, apex bluntly obtuse to rounded, margin

minutely or obscurely denticulate, base obtuse or cuneate

to subtruncate, drying chartaceous and pale grayish green

beneath, stellate-pubescent with appressed hairs 0. 1-0.4

mm diam., venation palmate with usually 5 major veins

from the base, 2° veins 3-4/side of the midvein. Inflo-

rescences terminal, bisexual, 1-4 cm long, often sub-

tended by small (15 x 12 mm) leaves, congested and

resembling a capitulum, bracteoles ca. 3 mm long, sub-

tending solitary flowers, $ flowers proximal, pedicels to

5 mm long in fruit, 6 flowers with pedicels ca. 2 mm

long. Male flowers with calyx 1.5-2 mm long, sepal lobes

ca. 1 mm long, petals 2-3 mm long, 0.3-0.4 mm wide,

glabrous except on the margin; stamens ca. 11, filaments

minutely hirsutulous, anthers 0.6-0.8 mm long. Female

flowers with 5 unequal sepals, 6-8 mm long in fruit,

petals absent, disk with 5 unequal lobes, ovary stellate-

tomentellous, styles distally 4 times bifid. Fruits ca. 5

mm long, borne on pedicels 3-5 mm long, sepals 6-8

mm long and 3.5-6 mm wide, columella 3-4.5 mm long;

seeds 3.2-3.8 mm long, 2.4-3 mm wide, ca. 2.2 mm

thick, rounded-oblong, caruncle ca. 1.8 mm wide.

Weedy plants of open sunny sites in seasonally

dry habitats, 0-300 elevation. Collected with flow-

ers in January-February, May, and August in Cos-

ta Rica and Nicaragua. While rarely collected in

Central America, it may be locally common. The

species ranges disjunctly from Texas to Argentina.

Croton argenteus is recognized by its herbaceous

habit, the soft grayish green color of the leaves

(especially the often whitish undersides), palmate

venation with usually five major veins, appressed

stellate hairs, short inflorescences often enclosed

within subtending leaves, and restriction to sea-

sonally deciduous vegetation. The paucity of col-

lections from southern Central America suggests

that the species is a recent introduction. Superfi-

cially, these plants resemble a number of weedy

Malvaceae.

Croton axillaris Mull. Arg., Linnaea 34: 126. 1865.

Shrubs or small trees 1-3.5 m tall, apparently unisex-

ual, leafy stems 2-4 mm thick, densely pubescent with

pale yellowish stellate hairs but soon becoming dark and

glabrescent; stipules 4-6 mm long, ca. 1 mm wide at

base, linear, densely stellate-pubescent. Leaves with pet-

ioles 1 2-23 mm long, 1 .2-1 .8 mm thick, densely stellate-

pubescent, hairs to 1.5 mm long, glands absent at apex;

leaf blades 6-14 cm long, 3-8 cm wide, ovate-triangular

to ovate-oblong or oblong, apex acute to acuminate with

a narrow tip, margin subentire, base rounded and trun-

cate to subcordate, drying thick-chartaceous, upper sur-

face with minute (0.2-0.4 mm) stellate hairs on a slightly

raised base, hairs with 5-7 lateral rays and 1 longer cen-

tral ray, lower surface densely covered with short-stalked

stellate hairs to 1 mm wide, venation pinnate, 2° veins

8-1 8/side. Male inflorescences terminal on short axillary

shoots before the leaves expand, 4-7 cm long, rachis ca.

1 mm thick, whitish stellate-pubescent, bracts 1-3 mm

long, caducous, pedicels 1-3 mm long; 6 flowers ca. 4

mm wide, densely stellate-tomentose on the exterior,

calyx lobes ca. 2 mm long, petals ca. 0.8 mm wide,

oblanceolate, glabrous abaxially and densely puberulent

on the inner face; stamens 1 1 , filaments 3—4 mm long,

sparsely puberulent, anthers 1-1.3 mm long. Female in-

florescences terminal on new lateral shoots, 2-4 cm long,

rachis densely stellate-tomentose, pedicles 0.5-2 mm long;

9 flowers crowded, 5-6 mm long, calyx lobes 2-3 mm

long, densely stellate-tomentulose on the exterior, ovary

ca. 3 mm long, densely puberulent, style branches 2 times

bifid in the proximal half. Fruits not seen.

Croton axillaris is recognized by its deciduous

forest habitat, stiff ovate-triangular leaves with

dense covering of stellate hairs, pinnate venation

with more than 1 0 pairs of secondary veins, and

compact inflorescences. The short-stalked stellate

hairs have approximately five to seven lateral rays

and one longer central ray. This species was de-

scribed from material collected from Granada,

88

FIELDIANA: BOTANY

Nicaragua, and is reported from northwestern

Costa Rica by Nelson Zamora (pers. comm.). The

species ranges northward to Guatemala in decid-

uous forest formations.

Croton billbergianus Mull. Arg., Linnaea 34: 98.

1865. C. grosseri Pax, Hot. Jahrb. Syst. 33: 290.

1903. C. pyramidalisj. D. Smith, Bot. Gaz. 35:

7. 1903. C. billbergianus ssp. pyrarnidalis (J. D.

Smith) Webster, Ann. Missouri Bot. Gard. 75:

1123. 1988. Figure 19.

Small trees or shrubs 3-1 5 m tall, bisexual, sap yellow

or orange, leafy stems 2-6 mm thick, scurfy-stellate with

appressed hairs with 8-20 peripheral rays, 0.2-0.5 mm

wide; stipules 4-7 mm long, linear, caducous. Leaves

with petioles 1.6-9(-12) cm long, 0.8-2 mm thick, scurfy-

stellate, with 2 lateral abaxial sessile saucer-like, patel-

liform or cupulate glands 0.7-1 .5 mm diam. at the apex;

leaf blades 9-25(-32) cm long, 4-1 7(-24) cm wide, ovate-

oblong, to oblong or ovate-elliptic, apex acuminate to

caudate-acuminate, narrowed tip 4-1 5 mm long, margin

subentire with minute (0.2 mm) glands along the margin,

ca. 6-10 glands/cm, base rounded and truncate to cor-

date with a shallow (0-7 mm) sinus, drying thinly char-

taceous and often greenish, surfaces with small (0.1-0.3

mm) stellate hairs and larger hairs along the veins, more

densely pubescent beneath, glandular punctate, venation

pinnate or subpalmate, 2° veins 6-1 I/side, basal 2° veins

sometimes strongly developed. Inflorescences terminal

or axillary, 1.5-16 cm long, sometimes with 2-4 prox-

imal branches to 1 1 cm long, bisexual or $, densely stel-

late, 2 flowers 3-8/rachis, solitary, on pedicels 1-8 mm

long, 0.8-1.6 mm thick; <5 flowers in glomerules of 3-5,

pedicels 2-8 mm long. Male flower buds 2.5-3.5 mm

diam., calyx 3—4 mm long, lobes 5, ca. 2 mm long, 3.5

mm wide at base, triangular, petals 3.4-3.8 mm long;

stamens 13-16, filaments ca. 4 mm long, glabrous dis-

tally, anthers 1.1-1.5 mm long. Female flowers with 5

sepals, 3-5.5 mm long, 1.2-3.3 mm wide, glabrous on

the interior, becoming reflexed, disk with lobes 0.3-0.4

mm thick; ovary 1.5-2 mm long, 2.3-3 mm diam., stel-

late-hispid, styles united to form a hispid column 0.5-

1 mm long, style branches 6-12 (more), 2-4 mm long,

glabrous distally. Fruits 7-8 mm long, 9-10 mm wide,

hispid, subtended by the prominent 5-lobed flat disk and

reflexed calyx, columella 4.5-5.5 mm long; seeds 4.5-5

mm long, 3.5—4 mm wide, 3-3.2 mm thick, oblong, ca-

runcle 0.7-1.5 mm wide.

Plants of lowland evergreen forest formations

on both Caribbean and Pacific slopes, 20-800 m

elevation. Flowering in April-July; fruiting in July-

December. The species ranges from Veracruz,

Mexico, to Panama.

Croton billbergianus is recognized by its yellow-

orange sap, larger thin ovate-oblong leaves often

slightly cordate at the base, sessile glands at the

apex of the petiole, longer anthers, reflexed 2 se-

pals, thick-lobed disk subtending the ovary, and

short hispid style column with 1 2 style branches.

The compound inflorescences, branched near the

base, are very distinctive but not common among

the collections seen. Leaves often dry greenish, but

there is considerable difference in the leaf shape

of different collections. Nevertheless, the leaves

are usually more clearly oblong than they are in

our other large-leaved species. Subspecies pyr-

arnidalis (Mexico to Honduras) has larger seeds

and stipules than those found in ssp. billbergianus.

Compare C. hoffmannii, where the ovary is sub-

tended by a pubescent disc.

Croton brevipes Pax, Bot. Jahrb. Syst. 33: 290.

1903. Figure 12.

Shrubs or small treelets 1-5 m tall, bisexual, leafy

stems 0.7-5 mm thick, often with long (ca. 12 cm) in-

temodes, stellate hairs short-stipitate, ca. 0.6 mm diam.,

with ca. 6-8 rays; stipules 2-6 mm long, subulate. Leaves

often opposite or subopposite (whorled) at distal or flow-

ering nodes, petioles 5-48 mm long, 0.7-2 mm thick,

stellate-pubescent, apex with 2 lateral yellowish glands

0.5-1.7 mm long, usually narrowly stipitate and saucer-

like distally, 0.5-1 . 1 mm wide; leaf blades 5-22 cm long,

2-9 cm wide, elliptic to ovate-elliptic, elliptic-oblong, or

narrowly obovate, apex acute or acuminate, margin with

broad rounded teeth 2-4 mm high, 5-8/side, sinuses of

the margin often with stipitate glands to 1 mm long, base

obtuse or cuneate and slightly rounded at the petiole,

drying thinly chartaceous, usually dark above and much

paler beneath, with scattered small (0. 1-0.6 mm) stellate

hairs and larger hairs on the veins both above and below,

venation pinnate, 2° veins 4-8/side. Inflorescences ter-

minal (pseudoaxillary), solitary, bisexual, 1 .2-5 cm long,

with 1-3 proximal 2 flowers on short (2 mm) pedicels,

<? flowers 1-2/bract, pedicels 1-3 mm long. Male flower

budsca. 1.3 mm diam., sepals 5, stellate-pubescent, 1.2-

1.7 mm long, petals 1.4-1.8 mm long; stamens 10-12,

filaments 1.8-2.5 mm long, glabrous, anthers 0.4-0.7

mm long. Female flowers with sepals 1.7-6 mm long, 1-

1.5 mm wide, oblong, glabrous within, often with teeth

on the edge; ovary 1.5-3 mm long, 1.8-3 mm diam.,

glabrous, styles 1-2 mm long, 2 times bifid. Fruits ca. 7

mm long, 5-6 mm wide, smooth, usually glabrous, sub-

tended by persisting perianth, columella 3-4 mm; seeds

3.8-5 mm long, 2.7-3.7 mm wide, 2-2.5 mm thick,

slightly striate-reticulate, caruncle 0.5-1 mm wide.

Plants of evergreen forest formations on both

the Caribbean and Pacific slopes, 20-800 m ele-

vation. Probably flowering and fruiting through-

out the year. The species ranges from northern

Costa Rica to Choco, Colombia.

Croton brevipes is recognized by the thin serrate

leaves with pinnate venation, broad rounded teeth,

and stipitate glands present in some sinuses along

the leaf margin as well as at the apex of the petiole.

Long internodes, opposite or whorled leaves at

some distal nodes, and the short inflorescences are

additional characteristics. This species is very

BURGER & HUFT: FLORA COSTARICENSIS

89

closely related to C. macrodontus Mull. Arg. of

Mexico, but there are minor distinctions and the

two are widely allopatric (cf. Webster & Huft,

1988).

Croton decalobus Mull. Arg., Linnaea 34: 80. 1865.

C. pittieri Pax in Pittier, Prim. Fl. Costar. 2:

338. Figure 16.

Shrubs 1-4 m tall, bisexual, much-branched, leafy

stems 1-4 mm thick, stellate-pubescent with hairs 0.4-

0.8 mm diam., sessile or on short (0.2 mm) stipes, gla-

brescent and reddish brown in age; stipules 4—8 mm long,

linear. Leaves with petioles 3-18 mm long, 0.8-1.3 mm

thick, densely stellate-pubescent, lacking glands at or

near the apex; leaf blades 3-10 cm long, 2-5 cm wide,

ovate-lanceolate to ovate-triangular or lanceolate, apex

tapering gradually and acute or acuminate, margin en-

tire, base acute to rounded or obtuse, drying chartaceous,

dark above with simple scabrous or stellate hairs ca. 0.3

mm diam., pale grayish beneath with a dense tomentum

of stellate hairs with 6-9 rays, venation pinnate, 2° veins

4— 13/side. Inflorescences terminal, 1-3 (rarely more on

leafless terminal stems), unisexual or bisexual, 3-10 cm

long, 9 flowers subsessile and with viscous glandular hairs,

solitary, <3 flowers 1 /bract, pedicels 1-2 mm long (prean-

thesis). Male flower buds 2.5-3 mm diam., densely short-

pubescent externally, petals 2-3 mm long, narrowly spat-

ulate; stamens ca. 1 5, filaments puberulent, anthers 0.7-

1 mm long. Female flowers ca. 6 mm long, sepals 4-6

mm long, ca. 1 mm wide, densely short-pubescent abax-

ially, with distinctive slender gland-tipped hairs along

the inner margin 0.8-3 mm long; ovary densely pubes-

cent, style branches ca. 2.5 mm long, pubescent, distally

bifid. Fruits ca. 5 x 5 mm, columela 3.7^1 mm long,

reddish, minutely fimbriate or glabrous; seeds 4-5.2 mm

long, 3-3.4 mm wide, 2.2-2.4 mm thick, smooth and

lustrous, caruncle 0.8-0.9 mm wide.

Rarely collected plants of evergreen forest for-

mations in the central highlands, 1100-1800 m

elevation. Flowering in June-July; fruiting in July-

August. This species has been collected only in the

eastern Meseta Central, from Tibas and Escazu to

Cartago and Agua Caliente. The species is also

known from central Honduras and Guatemala.

Croton decalobus is recognized by its often nar-

rowly ovate-triangular leaves lacking glands at the

petiole/blade interface, pinnate venation, and un-

usual gland-tipped hairs along the inner edge of

sepals in 9 flowers. The apex of the gland-tipped

hairs is often elongate, resembling anthers on sta-

mens.

Croton draco Cham. & Schldl., Linnaea 6: 360.

1831. Cyclostigma panamensis Klotzsch in

Seem., Hot. voy. Herald 105. 1853. Cy. denti-

culatum Klotzsch in Seem., Bot. voy. Herald

105. 1853. Cr. panamensis (Klotzsch) Mull. Arg.

in DC., Prodr. 15 (2): 546. 1866. Cr. steyer-

markianus Croizat, J. Arnold Arbor. 21: 86.

1940. Cr. triumfettoides Croizat, J. Arnold Ar-

bor. 21: 86. 1940. Cr. draco ssp. panamensis

(Klotzsch) Webster, Ann. Missouri Bot. Gard.

75: 1120. 1988. Figure 18.

Trees or shrubs 2-1 5(-30?) m tall, bisexual, leafy stems

2-8 mm thick, densely pubescent with scurfy or stellate

hairs 0.2-0.5 mm diam. or with longer slender hairs to

1 mm; stipules 3-10 mm long (to 12x4 mm in Mexico),

linear or lanceolate. Leaves sometimes opposite at distal

nodes, petioles 4.2-14(-20) cm long, 1-3.5 mm thick,

densely stellate-scurfy, adaxial apex with 2-8 patelliform

or saucer-like glands 0.4-1 .7 mm wide, sessile or stipitate

and 0.4-3.5 mm long; leaf blades (7-)l l-26(-30) cm

long, (4-)6-16(-23) cm wide, ovate-triangular to ovate,

apex gradually narrowed and acuminate, tip 8-22 mm

long, margin minutely (0.2-1 mm) denticulate or sub-

entire, base rounded and truncate to cordate, drying

chartaceous, dark above with stellate or scurfy hairs to

0.4 mm diam., grayish beneath with scurfy or stellate

hairs 0.3-1 mm diam., stellate hairs with 8-14 rays,

venation palmate or subpalmate with 3 major veins, 2°

veins 4-10/side of the midvein, 3° veins subparallel.

Inflorescences terminal, bisexual or 3, 7-35(-70) cm long,

with proximal 9 flowers or cymules with 1 9 flower and

1-several <5 flowers, or with many cymules of 3-15 6

flowers, bracteoles 1-1.5 mm long, $ pedicels 1-4 mm

long, <? pedicels 3-8 mm long, slender. Male flowers 3-

6 mm wide, calyx ca. 2.2 mm long, calyx lobes 5, 1-2.3

mm long, triangular, petals ca. 2 x 0.5 mm; stamens

13-20, filaments 1.5-3 mm long, glabrous, anthers 0.4-

0.8 mm long. Female flowers densely pubescent exter-

nally, sepals 5, 1.3-2.5 mm long, 1-1.5 mm wide, gla-

brous within, petals 1-2 mm long, usually filiform, disc

inconspicuous; ovary 2.5-4 mm diam., pubescent, styles

deeply or partly bifid (6/flower), 2.5-3.5 mm long. Fruits

5-6 mm long, 6-8 mm wide, densely yellowish scurfy-

stellate, pedunculate, subtended by the closely appressed

sepals (rarely rotate), columella 3-4 mm long; seeds 3.8-

5 mm long, 2.4-3.6 mm wide, 2-2.5 mm thick, oblong-

ellipsoid, with lateral raised ridges (sometimes chevron-

like), caruncle ca. 2 mm wide.

Common plants of partly deciduous and ever-

green forest formations of the central highlands,

(10-)700-2200 m elevation. Probably flowering

throughout the year but collected most often in

June-September. This species is rarely colleced

below 700 m but was said to be common near

Golfito (Allen 6627). The species ranges from Ve-

racruz, Mexico, to Colombia.

Croton draco is recognized by its larger ovate-

triangular leaves with as many as 1 2 glands at the

apex of the petiole, long inflorescences, 6 flowers

present with proximal 9 flowers in bisexual inflo-

rescences, pedicellate 9 flowers with relatively small

calyx lobes and inconspicuous disk, and seeds with

raised lateral ridges. The $ inflorescences are often

90

FIELDIANA: BOTANY

densely flowered with many closely spaced glom-

erules of 5-1 1 flowers (distal fascicles may have

one to a few $ flowers). The complex indument of

both scurfy and stellate hairs is not found in all

collections. Targud and copalchi are common

names applied to this and similar Croton species.

This species is similar to C. xalapensis and C.

hoffmannii in general appearance, but the latter

two species do not have <5 and 2 flowers together

in the same glomerules.

Croton glandulosus L., Syst. ed. 10. 1275. 1759.

Herbs, erect or decumbent, to 0.6 m tall, bisexual,

leafy stems 1-2.5 mm thick, with appressed stellate hairs

0.4-1.3 mm wide; stipules to 0.5 mm long, gland-like

or absent. Leaves often opposite below branching nodes,

petioles 2-9 mm long, ca. 0.6 mm thick, densely stellate-

pubescent, with paired lateral subsessile glands at apex,

ca. 0.5 mm diam.; leaf blades 7-35 mm long (larger in

the northern part of its range), 6-16 mm wide, broadly

ovate to ovate-elliptic or narrowly oblong, apex rounded,

margin crenate with 3-5 rounded teeth/cm, base obtuse

to truncate, drying grayish green, stellate-pubescent above

and beneath, venation pinnate or subpalmate. Inflores-

cences terminal and pseudoaxillary, to 2 cm long and 5

mm wide, developing 2-4 fruits/node; <3 flowers with 7-

1 3 stamens; 9 flowers with deeply bifid styles (appearing

as 6). Fruits 4-5 mm long, splitting at the apex but often

remaining united beneath, covered with thin stellate hairs

ca. 0.8 mm wide, columella ca. 3 mm long, slender; seeds

ca. 3 mm long, 2-2.5 mm wide, oblong, lustrous.

Croton glandulosus is recognized by the short

herbaceous habit, thin stellate-appressed hairs,

small leaves with prominent rounded teeth, sub-

sessile saucer-shaped glands at the apex of the pet-

ioles, and short inflorescences. Standley (1937) re-

ported this species from Cost Rica, but we have

seen no material from southern Central America.

The species ranges from the southeastern United

States, Mexico, and the West Indies to South

America.

Croton hirtus L'Her., Stirp. Nov. 17, t. 9. 1785.

C. glandulosus L. subsp. hirtus (L'Her.) Croizat,

Bull. Torrey Dot. Club 75: 401. 1948. Figure 10.

Annual herbs 20-90 cm tall, bisexual, leafy stems 0.8-

6 mm thick, hispid with stellate hairs having small (0.3-

0.7 mm) thin basal rays and 1 central ray 2-3.5 mm

long, often dense and retrorse; stipules 2-4.5 mm long,

ca. 0.5 mm wide, linear, pubescent. Leaves with petioles

3-30 mm long, 0.3-1 mm thick, with thin stellate hairs

to 2 mm long, with paired (1-4) stalked yellowish glands

0.5-1.2 mm long near the apex; leaf blades 1.3-9 cm

long, 0.9-5.8 cm wide, ovate to ovate-triangular or ovate-

oblong, apex acute to rounded, margin with 10-25

rounded teeth/side, base rounded and truncate to broad-

ly obtuse, drying thinly chartaceous, greenish to yellow-

brown, upper surface with thin simple hairs 0.3-1 mm

long, lower surface stellate with small (1 mm diam.) and

longer (2 mm) hairs along the veins, venation palmate

with 3 major veins, 2° veins 1-4/side of midvein. Inflo-

rescences terminal, 1-3, bisexual, 1-10 cm long, often

subtended by small leaves, peduncles 0-28 mm long, ca.

0.5 mm thick, stellate-pubescent, 9 flowers 3-12, sub-

sessile, 3 flowers 4-9, pedicels 1-3 mm long, slender,

rachis with gland-tipped hairs and linear bracts with 1-

3 slender gland-tipped segments 0.5-5 mm long. Male

flower buds ca. 1.8 mm diam., densely pubescent exter-

nally, sepals 5, 1-1.5 mm long, stellate externally; sta-

mens 8-1 2, filaments 0.8- 1.5 mm long, glabrous, anthers

0.3-0.5 mm long. Female flowers with 4 unequal sepals

3.5-4 mm long, 0.5-1 mm wide, oblanceolate to linear,

pubescent; ovary ca. 3 x 2 mm, styles separate above

the base, 1.5-2.5 mm long, bifid. Fruits ca. 4 mm long,

3.5-4.5 mm wide, stellate-pubescent (glabrous), sepals

to 6 mm long, columella 2.8-3.2 mm long; seeds 2.8-

3.6 mm long, 2-2.8 mm wide, 1 .4-1 .8 mm thick, oblong-

lenticular, smooth with surface minutely reticulate, lus-

trous, caruncle ca. 1.5 mm wide.

Weedy plants of open sunny sites in evergreen

and deciduous areas, 0-1700 m elevation. Flow-

ering and fruiting material has been collected

mostly in March-August in southern Central

America. In Costa Rica, it is most often collected

on the Pacific slope and lowlands below 1200 m

elevation. The species ranges from Mexico to Bra-

zil, mostly in deciduous vegetation.

Croton hirtus is recognized by its annual weedy

habit, distinctive (usually retrorse) pubescence,

stipitate glands at base of the blade (often difficult

to see or absent), simple hairs on upper leaf sur-

faces, and short inflorescences with unusual bracts

with slender segments that resemble gland-tipped

hairs. The stellate hairs of the stem, with a basal

circle of short thin rays and a central erect large

ray, are distinctive, but the small basal rays are

often difficult to see. Material of this species was

often placed under Croton glandulosus, but that

species lacks the unusual hispid hairs and has ses-

sile petiolar glands and floral bracts without glands.

Croton hoffmannii Mull. Arg., Linnaea 34: 86.

1 865. C. hoffmannii var. incana Mull. Arg., Lin-

naea 34: 86. 1865. C. hoffmannii var. viridis

Mull. Arg., Linnaea 34: 86. 1865. Oxydectes tur-

rialva O. Ktze. and C. turrialva O. Ktze. (as

syn.), Rev. gen. 2: 614. 1891. Figure 19.

Shrubs or small trees 1 . 5-6 m tall, bisexual, leafy stems

2-6 mm thick, densely stellate-pubescent with short-

stipitate (0.1-0.8 mm) hairs 0.3-0.7 mm diam.; stipules

5-7 mm long, linear, caducous. Leaves sometimes op-

posite at distal flowering nodes, petioles 2-15 cm long,

1-3 mm thick, densely stellate-pubescent, usually with

BURGER & HUFT: FLORA COSTARICENSIS

91

2 latcral/abaxial saucer-like or patelliform sessile glands

near the apex, 0.7-1.3 mm wide; leaf blades 7-22 cm

long, 4-19 cm wide, ovate to ovate- triangular, acute to

acuminate at the apex, margin minutely dentate with

small (0.3-1 mm) gland-tipped teeth, ca. 3-9 teeth/cm,

base rounded and cordate to truncate, drying thinly char-

taceous, upper surface with simple or stellate hairs, lower

surface more densely pubescent, stellate hairs with 8-14

rays, 0.3-0.7 mm diam., venation palmate or subpal-

mate with 3 prominent veins from base, 2° veins 3-87

side of midvein. Inflorescences 8-30 cm long (often pen-

dulous in life), terminal, 1-4, usually bisexual with 1-

1 2 proximal solitary 2 flowers or proximal cymules with

1 2 and 2 6 flowers, flowers or fascicles usually distant

along the rachis, 2 pedicels 1-2 mm long, $ pedicels 1-

3 mm long, distal bracts to 6 mm long subtending 3-9

6 flowers. Male flower buds ca. 3 mm diam., calyx ca.

4 mm long, calyx lobes 1-2.5 mm long, 1.5-2.7 mm

broad at base, petals 5, ca. 3 mm long; stamens ca. 16,

anthers 0.7-0.8 mm long. Female flowers ca. 6-7 mm

long, calyx lobes 5, unequal and imbricate in bud, 3-4

mm long, 1.5-5 mm broad, triangular to ovate, glabrous

within, disk with dense radiating hairs 0.7 mm long;

ovary densely hirsute, ca. 3 mm diam., styles with short

(0.5 mm) pubescent column, each style with 4 glabrous

branches ca. 3 mm long. Fruits ca. 8 x 10 mm, sub-

tended by the rotate or reflexed sepals, columella 6-7.5

mm long; seeds 6-8 mm long, 4.3-5 mm wide, 3.2-4

mm thick, smooth or with some irregular raised areas,

caruncle 2.6-3 mm wide.

Plants of open weedy sites in evergreen forest

formations 900-1600 m elevation. Flowering in

June-August; fruiting in October-December. In

Costa Rica, this species appears to be restricted to

the area between the eastern part of the Meseta

Central and the northern edge of the Cordillera de

Talamanca (Rio Virilla eastward to the Orosi val-

ley). Specimens determined as this species have

also been collected in Mexico.

Croton hoffmannii is recognized by its larger

ovate-triangular leaves with sessile glands at the

apex of the petiole, serrulate margins, long inflo-

rescences with uncrowded flowers, larger 2 flowers

with ovary subtended by a densely pubescent disc

(easily seen in fruit because of the rotate or reflexed

sepal lobes), larger seeds, and very limited geo-

graphic range. Some inflorescences have proximal

cymules with 1 2 flower and 2 $ flowers. The leaves

are often ovate-triangular and usually dry yellow-

ish green. The calyx is united almost 50% in both

$ and 2 flowers. The restricted flowering period,

flowers well separated along the inflorescence ra-

chis, and calyx united to form clearly visible cups

help distinguish this species from the vegetatively

similar C. draco, C. pungens, and C. xalapensis.

Croton jimenezii Standl. & Valerio, Publ. Field

Mus. Nat. Hist., Bot. Ser. 18: 604. 1937. Figure

19.

Trees or shrubs, 3-15 m tall, bisexual or unisexual,

leafy stems 2-8 mm thick, densely pubescent with short

(0.2 mm) reddish brown scurfy-stellate hairs ca. 0.3 mm

wide at the flattened apex, the hairs often with slender

central rays to 1.5 mm long; stipules 3-5 mm long, 0.5-

2 mm wide at base, pubescent, caducous. Leaves with

petioles 3.6-14.5 cm long, 0.8-3.5 mm thick, densely

brownish scurfy-stellate hirsutulous, often contracted at

apex and base when dried, apex with 2-5 glabrous stip-

itate conical glands 0.5-1 .5 mm long, 0.4 mm wide; leaf

blades 8-24 cm long, 4—13 cm wide, ovate to ovate-

triangular or ovate-oblong, apex acuminate with narrow

tip 6-14 mm long, margin entire or subentire (glandular-

crenate), base rounded and truncate or subcordate, dry-

ing chartaceous, upper surface with scurfy-stellate hairs

ca. 0.2 mm wide, lower surface with similar hairs 0.2-

0.4 mm wide, hairs to 2 mm long sometimes present

near base and along midvein, venation pinnate or sub-

palmate, 2° veins 7-10/side. Inflorescences terminal,

usually solitary, unisexual or bisexual, 4-30 cm long, ca.

2 cm wide, peduncle 2-3.5 mm thick, pubescent as the

stems, bracts 0.7-3 mm long, subtending 1 subsessile 2

flower or 1-56 flowers on pubescent pedicels 2.5-6 mm

long, 0.2-0.4 mm thick. Male flower 5-10 mm wide at

anthesis, pubescent externally, calyx lobes 1.5-2.5 mm

long, petals 2-3 mm long; stamens 21-31, filaments ca.

3 mm long, pubescent only at the base, anthers 0.6-0.8

mm long. Female flowers pubescent externally, calyx lobes

5, 3-1 1 mm long, 1-3 mm wide, spathulate to oblong;

ovary ca. 3 mm diam., covered with many-pointed stel-

late hairs 0.5-1 mm wide, styles 3-4 mm long, undivided

for ca. 1 mm, twice bifid (12 distal parts). Fruits ca. 6

mm long (only 1 seen); seeds 3.7-5 mm long, 3-4 mm

wide, ca. 2 mm thick, oblong-lenticular, surface smooth

or very slightly rugulose, caruncle 0.8-2 mm wide.

Trees of wet evergreen montane forests near the

continental divide of the central volcanic high-

lands and Cordillera de Talamanca, (1000-)! 500-

2500 m elevation. Flowers have been collected in

December-May and July. This endemic species

ranges from near Zarcero eastward to Sta. Cruz de

Turrialba and is also known from a single collec-

tion from along the Inter- American Highway about

27 km north of San Isidro del General.

Croton jimenezii is recognized by the dense pu-

bescence of brownish or yellowish stellate/scurfy

hairs, larger ovate-triangular leaves, oblong 2 calyx

lobes that enlarge as the fruit develops, $ flowers

with 21-30 stamens, and restricted montane hab-

itat. The hairs of the stems often have very short

(0.1 mm) stalks and a flattened reddish brown

distal portion with short marginal teeth, giving a

rufous scurfy-stellate appearance. In addition, the

hairs often have one transparent central ray be-

coming 1-2 mm long. Though little collected, the

species has been noted as locally common and

called targua. Collections with only $ flowers may

be very difficult to separate from C. draco.

92

FIELDIANA: BOTANY

Croton jutiapensis Croizat, Publ. Field Mus. Nat.

Hist., Bot. Ser. 22: 450. 1942. Figure 16.

Small shrubs 0.5-1 (-2) m tall, bisexual, leafy stems

0.7-3 mm thick, stellate-pubescent with hairs ca. 0.5 mm

diam., sometimes with longer rays 0.5-1.5 mm long,

whitish or yellowish, glabrescent and dark in age; stipules

3-8 mm long, linear, caducous. Leaves with petioles 3-

12(-32) mm long, 0.4-1.3 mm thick, densely stellate-

pubescent, with 2 (3-4) lateral/abaxial stipitate conical

yellowish glands 0.4-1 m long, 0.2-0.7 mm wide at apex;

leaf blades 1.7-9(-l 1) cm long, 0.8^t.3(-5.5) cm wide,

ovate-triangular to ovate-lanceolate or ovate-elliptic, apex

acute or acuminate, margins with 7-19 short (0.5-2 mm)

teeth/side, base cuneate to rounded and subcordate, dry-

ing chartaceous, upper surface usually dark with stellate

hairs ca. 0.5 mm diam., lower surface densely stellate

and pale colored, venation pinnate or subpalmate, 2°

veins 3-8/side. Inflorescences terminal or axillary, sol-

itary, 2-5(-7) cm long, usually bisexual, peduncles 5-15

mm long, densely stellate-pubescent, 9 flowers 1-7, sub-

sessile or short pedicellate, $ flowers solitary, pedicels

ca. 2 mm long, bracteoles 1-3 mm long, linear. Male

flower buds ca. 2 mm diam., sepals 5, 1-2 mm long,

0.8-1 mm wide, triangular, petals 5, 1.7-2.2 mm long,

ca. 1.1 mm wide, oblong to spathulate; stamens ca. 1 1,

filaments 1.5-3.5 mm long, glabrous, anthers 0.4-0.7

mm long. Female flowers 3.5-8 mm long, sepals 1.5-5

mm long, becoming 5-8 mm long in fruit, subequal or

unequal; ovary ca. 3 x 4 mm, densely stellate-hispid,

styles 2—4 mm long, bifid to the base (6). Fruits 4.5-6

mm long, densely hispid, columella 3-4 mm long; seeds

3.3-4 mm long, 2-3.3 mm wide, 1.5-1.8 mm thick, ob-

long-ellipsoid, smooth, lustrous, caruncle 0.8-1.8 mm

wide.

Common plants in open sunny sites in season-

ally dry deciduous woodland formations, 0—400

m elevation (to 1 1 00 m in Honduras and Gua-

temala). Flowering in April-August; fruiting in

July-October. The species ranges from the Peten

area of Guatemala along the Pacific slope to Guan-

acaste Province in Costa Rica.

Croton jutiapensis is recognized by the short-

shrubby habit with older stems becoming blackish

and glabrous, seasonally dry habitat, leaves usu-

ally ovate-lanceolate with lateral stipitate glands

near the apex of the petiole, pinnate venation, and

short inflorescences. Many Costa Rican collec-

tions have been identified as C. costaricensis, but

that name is a synonym of C. ortholobus, a species

of higher elevation.

Croton lanjouwensis Jabl., Mem. New York Bot.

Gard. 12: 158. 1965. C. matourensis Abulet var.

benthamianus Mull. Arg., Linnaea 34: 95. 1865.

C. benthamianus (Muell. Arg.) Lanjouw. Eu-

phorb. Surinam 17. 1931, non C. benthamianus

Mull. Arg. in Mart., Fl. Bras. 1 1 (2): 106. 1874.

Figure 17.

Trees 7-40 m tall, bisexual, leafy stems 1-6 cm thick,

covered with flat rounded-appressed peltate hairs 0.3-

0.5 mm diam. and yellowish brown dried; stipules 6-10

mm long, ca. 1.2 mm wide at base, covered with peltate

hairs, caducous. Leaves with petioles 11-55 mm long,

0.7-1.7 mm thick, covered with peltate scales, with 2

adaxial lateral patelliform glands 0.7-1.6 mm wide at

the apex; leaf blades 7- 1 6 cm long, 3-6 cm wide, elliptic-

oblong to oblong or elliptic, apex acute to short-acu-

minate with tip 3-8 mm long, margin entire, base acute,

drying stiffly chartaceous, dark brown to grayish brown,

glabrous above, sparsely to covered beneath with peltate

hairs 0.3-0.4 mm diam., venation pinnate with 1 1-22

veins/side. Inflorescences terminal, 1-4, 6-18 cm long,

racemose, bisexual, peduncles 12-60 mm long, ca. 2 mm

thick, with peltate hairs, with 1-6 proximal 9 flowers on

pedicels to 5 mm long (to 1 5 mm in fruit), 3 flowers in

distal groups of 3-5, bracts 1-4 mm long, lepidote. Male

flower buds ca. 2 mm diam., covered with peltate hairs,

calyx lobes 5, valvate, 2-2.5 mm long, petals to 2 mm

long; stamens ca. 12, anthers 0.6-0.7 mm long. Female

flowers ca. 6 mm long, 8-10 mm wide, calyx lobes 5, 3-

4.5 mm long, triangular, valvate, with stellate hairs on

the inner surface and peltate externally, petals absent;

ovary ca. 3.5 mm diam., styles ca. 4 mm long, twice

bifid. Fruits (not seen) ca. 5 mm long, columella ca. 4

mm long; seeds ca. 3.5 mm long, rounded.

Trees of wet evergreen rain forest formations on

the Caribbean slopes between 200 and 800 m el-

evation. Flowering in March and July in southern

Central America. This species ranges from near

the Costa Rican-Panama border to the eastern

Amazon Basin.

Croton lanjouwensis is recognized by its large

stature, flat rounded-appressed peltate hairs cov-

ering many surfaces, paired glands at the apex of

the petioles, pinnate venation with many second-

ary veins, and larger 9 flowers. We have seen only

a single Costa Rican collection (A. Chacon 182 CR,

F, MO) from 800 m elevation in Parque Interna-

cional La Amistad. The large height attained by

these trees may explain why they are not collected

more often. This species is closely related to C.

matourensis Aublet of South America.

Croton lobatus L., Sp. PI. 1005, 1 753. Astraea see-

mannii Klotzsch in Seem., Bot. voy. Herald 103,

1853. C. lobatus var. seemannii (Klotzsch) Mull.

Arg. in DC., Prodr. 15 (2): 669. 1866. Figure 2.

Herbs 0.2-0.9(-1.5) m tall, bisexual, often with distal

leaves and shoots from congested nodes, leafy stems 1-

4.5 mm thick, with sessile-stellate hairs 0.3-1 .8 mm long

or with only 1 ray of the hair developing and simple;

stipules 2-6 mm long, 0.5-0.8 mm broad at base, lan-

ceolate to linear (sometimes deeply split and more than

2/node). Leaves with petioles 3-11 cm long, 0.4-1 .3 mm

thick, sparsely puberulent with mostly simple hairs to 2

mm long, with minute lobed or digitate glands 0.1-0.4

BURGER & HUFT: FLORA COSTARICENSIS

93

mm long at the adaxial apex; leaf blades 3-9 cm long,

2-10 cm wide, 3-5-lobed with deep narrow sinuses (or

unlobed and lanceolate), central lobe elliptic to oblan-

ceolate, apices acuminate, margins of the major lobes

with 1 2-20 teeth/side, base truncate to subcordate, dry-

ing thinly chartaceous, greenish to brown, with mostly

simple hairs 0.3-1 mm long above and below, venation

palmate with 3-5 veins (unlobed leaves pinnately veined

with ca. 5 veins/side). Inflorescences terminal, 2-6(-15)

cm long, racemose, bisexual with l-3(-7) proximal sol-

itary 9 flowers and 4-12 distal <5 cymules, bracts ca. 2

mm long below 9 flowers and 1 mm long below 3 flowers,

9 pedicels ca. 1 mm long and densely pubescent, to 3

mm long in fruit; <5 flowers solitary or in cymules of 2-

5, 6 pedicels ca. 2 mm long and glabrous. Male flower

buds ca. 1.2-1.8 mm diam., globose, calyx lobes 5, ca.

1 . 1 mm long, imbricate and rounded, petals 1 .2-1 .5 mm

long, 0.5-1 mm wide; stamens (8-)12-15, filaments to

1 mm long, glabrous, anthers ca. 0.3 x 0.4 mm. Female

flowers 4-5 mm long, sepals 5, 4-7 mm long, 1-2 mm

wide, oblanceolate to spatulate, sparsely pubescent, with

minute teeth or stalked glands near the base, disc of 5

segments ca. 0.3 mm long; ovary 3-4 mm long, pubes-

cent with stellate or simple hairs (rarely glabrous), styles

2-4 mm long, 2 times bifid in the distal half. Fruits ca.

6 mm long, 6 mm diam., oblong, 3-lobed, columella 4—

5 mm long; seeds 4.5-5.5 mm long, 2.7-3.5 mm wide,

2.5-3 mm thick, oblong-rectangular, slightly rugulose

with slanted transverse ribs, caruncle 1.4-2 mm wide,

reniform-peltate.

Plants of open sunny sites in lowland evergreen

to deciduous formations, 0-800 m elevation (in

Central America). Often found in sandy stream-

sides or in weedy fields and roadsides. Probably

flowering and fruiting primarily in the wet season,

May-December. Though weedy and wide-rang-

ing, this species is infrequently collected in Central

America; it has been collected only a few times in

the Pacific lowlands of central and northern Costa

Rica (20-350 m). It ranges from Florida and the

Bahamas to Peru and Brazil and is found in west-

ern and northeastern Africa.

Croton lobatus is distinguished by its short weedy

habit, deeply lobed leaves, leaf surfaces with most-

ly simple hairs, 9 flowers with five to seven long

narrow sepals, and unusual seeds. No other species

of Croton in Costa Rica has leaves with compa-

rably deep sinuses.

Croton mexicanus Mull. Arg., Linnaea 34: 113.

1865. Figure 16.

Trees 4-15 m tall, bisexual, leafy stems 1.5-4 mm

thick, stellate-pubescent with flat appressed somewhat

peltate hairs 0.2-0.4 mm diam., stems becoming grayish

or reddish brown; stipules 3-4 mm long, linear. Leaves

with petioles 15-58 mm long, 0.8-2 mm thick, ap-

pressed-pubescent with stellate or peltate-like hairs, 2

lateral glands present near the apex of the petiole, 0.7-

1.5 mm long, 0.4-0.7 mm diam. at apex, conical-cu-

pulate; leaf blades 5-14(-16) cm long, 2-7 (-9) cm wide,

ovate-elliptic to narrowly ovate, lanceolate or elliptic,

tapering gradually to the acute or acuminate apex, mar-

gin minutely dentate with glandular teeth 0.2-0.4 mm

high, 3-5 teeth/cm, base cuneate to rounded, drying

chartaceous, darker above with sparse stellate-peltate

hairs 0.1-0.4 mm diam., paler and more densely pu-

bescent beneath with larger hairs, venation pinnate or

subpalmate with basal 2° veins usually reaching the mid-

dle of the blade, 2° veins 3-6/side of midvein. Inflores-

cences terminal, 1-4, unisexual (rarely with bisexual

glomerules), 2-13 cm long, 9 flowers 1-3, 9 pedicels 1.3-

3.5 mm long, 1.2-1.5 mm thick, bracteoles ca. 1 mm

long, <3 flowers in glomerules of 2-5 or solitary, stellate-

pubescent, 3 pedicels 2-8 mm long, slender. Male flower

buds ca. 3 mm diam., calyx lobes 5, 1.5-2 mm long, 1.3

mm wide, petals 5, ca. 2 mm long; stamens ca. 14-16,

anthers 0.6-0.9 mm long, almost as wide. Female flowers

with 5 calyx lobes 2.5-3 mm long, ca. 1.3 mm wide;

ovary 2.3-2.7 mm long, 2-3.3 mm diam., densely stel-

late-pubescent, style branches pubescent in the lower

half, glabrous and bifid in the distal half (6). Fruits 10-

12 mm long, 9-10 mm wide, with stellate-scurfy hairs,

columella ca. 8 mm long; seeds 6-7 mm long, 4.5-4.8

mm wide, 2.5-3.2 mm thick, surface smooth but with

irregular raised areas, caruncle 2-2.7 mm wide.

Plants of evergreen forest formations on the Pa-

cific slope and continental divide of the Cordillera

de Tilaran, 1400-1600 m elevation. Flowering in

February and June-October; fruiting in August-

November. The preceding description is based on

material collected from the area around the Mon-

teverde community and Cloud Forest Reserve in

the Cordillera de Tilaran. The material placed here

appears to be a disjunct population of a species

otherwise only known from Mexico.

Croton mexicanus is recognized by its long pet-

ioles with two prominent glands near the apex,

narrowly ovate-elliptic leaves with prominent bas-

al 2° veins, appressed flat-stellate or scurfy pubes-

cence on many parts, stamens 14— 16/flower, and

slightly rugose seed surfaces. The distally flattened

stellate hairs with more than 1 5 radiating periph-

eral rays are distinctive and often have a raised

brownish center. The rays may be united near the

elevated center and somewhat peltate, but more

three-dimensional irregularly stellate (scurfy) hairs

may also be present. The trees are often conspic-

uous because of the silvery undersides of their

leaves. Despite the restricted area from which our

collections have been made, the Monteverde ma-

terial exhibits considerable variation; one collec-

tion has spikes with bisexual glomerules (Haber &

Zuchowski 10714). Placement of this material un-

der C. mexicanus is tentative; we have seen no

authentic material of C. mexicanus. Croton oer-

stedianus Mull. Arg. is also closely related but has

leaves that are bluntly retuse at the apex and grows

94

FIELDIANA: BOTANY

at lower elevations in Honduras and Nicaragua.

Collections placed here were earlier determined

and distributed as C. monteverdensis, an unpub-

lished name.

Croton niveus Jacq., Enum. pi. syst. 32. 1760. Fig-

ure 17.

Shrubs or small trees 2-1 2(-20?) m tall, bisexual, leafy

stems 1.5-4.5 mm thick, whitish, covered with flat

rounded peltate hairs 0.2-0.4 mm diam., usually with a

small brown center and whitish circumference; stipules

3-9 mm long, linear, caducous. Leaves with petioles 7-

32 mm long, 0.7-1 .8 mm thick, with peltate hairs, glands

absent near the apex; leaf blades 3-14 cm long, 2-10 cm

wide, broadly ovate to ovate-orbicular or ovate-trian-

gular, tapering gradually to an acuminate or acute apex,

margin serrate to subentire, base rounded and truncate

to obtuse, drying chartaceous, upper surface dark and

glabrous or with scattered peltate hairs, lower surface

grayish or silvery with a dense covering of peltate hairs

0.2-0.5 mm diam., venation palmate or subpalmate,

with prominent basal lateral veins, 2° veins 3-5/side of

midvein. Inflorescences usually axillary, 2-1 1 cm long,

bisexual or $, with peltate hairs throughout, with 1-3

proximal 9 flowers on pedicels 4-18(-28) mm long, 0.4-

1 .7 mm thick, distal bracts 0.5-1 .5 mm long, subtending

solitary $ flowers on pedicels 1-6 mm long, ca. 0.6 mm

thick. Male flower buds 2-3 mm diam., sepal lobes 1.3-

2.2 mm long, triangular, petals 2-3 mm long, ca. 1 mm

wide, narrowly oblong, with densely ciliolate edge and

glabrous surfaces; stamens 10-1 5, filaments 2.2-3.3 mm

long, glabrous, anthers 0.6-1 .3 mm long. Female flowers

with sepals 2.5-4 mm long, 2.1-3 mm wide at base,

petals 1-3 mm long, 1.2 mm wide, narrowly oblong,

with a densely ciliolate white edge; ovary 2.5-5 mm long,

2.5-5 diam., covered with stellate-peltate hairs, styles

2.5-3 mm long, bifid to multifid distally. Fruits 9-24

mm long, 9-20 mm wide, differing greatly in size in

different collections, usually becoming covered with short

projections terminating with irregular stellate hairs, col-

umella 7.5-16 mm long; seeds 6.5-16 mm long, 5.3-1 1

mm wide, 3-5 mm thick, oblong, dark brown mottled

with white or yellowish brown, caruncle 1.5-2.2 mm

wide.

Plants often seen in hedgerows and roadsides in

deciduous and partly deciduous forest formations

(rare in evergreen areas), 50-1800 m elevation.

Flowering material has been collected in March-

August and November-December. The species (in

a wide sense) ranges from Mexico to Venezuela.

Croton niveus is recognized by the flat appressed

rounded peltate hairs on almost all outer surfaces,

ovate-triangular leaves often with silvery under-

surfaces, and larger fruits and seeds. The hairs

covering the ovary are usually more stellate (with

deeply divided rays) than hairs on other surfaces,

and they often become raised on projections as the

fruit develops (but see below). This species is often

used as a hedgerow plant. Dried leaves and bark

have been used in Guatemala for medicinal pur-

poses (Standley & Steyermark, 1949, pp. 73, 79).

The common names copalchfand quisarrd copal-

c/» are said to be based on the Mayan name copal-

C/H? (Pittier, 1957, p. 59).

Cultivation and use by indigenous peoples over

many centuries may account for the great variation

in fruit and seed size seen in different collections.

For this reason, we prefer a broad interpretation

of this species. The senior author at first included

C. reflexifolius H.B.K., C. eluterioides Lotsy, and

C. guatemalensis Lotsy as synonyms under this

species. However, a reviewer pointed out that these

species have peltate hairs on the ovary, not stellate

hairs as in C. niveus (sensu stricto). There are a

few specimens in which the ovary is covered with

hairs that appear intermediate between peltate and

stellate. It is on the basis of such collections that

it seems likely a broader interpretation of C. niveus

will prove more useful. The reader should note

that the material placed under this name may rep-

resent a complex of closely similar species.

Croton ortholobus Mull. Arg., Flora 55: 9. 1872.

Oxydectes costaricense Kuntze, Rev. gen. 2:614.

1891. C. costaricensis Pax in Pittier, Prim. Fl.

Costar. 2: 331. 1900. Figure 16.

Small shrubs 0.5-2.5 m tall, bisexual, leafy stems 0.9-

4 mm thick, densely stellate-pubescent and apparently

hispid with central sharp rays to 2.2 mm long, older

stems glabrescent and dark reddish brown or black; stip-

ules 2-5(-9) mm long, 0.2-0.4 mm wide, linear, drying

dark, deciduous. Leaves with petioles 4-30(-52) mm

long, 0.5-0.9 mm thick, stellate-pubescent and hispid,

with paired stipitate-cupulate glands at leaf base beneath,

0.5-1.5 mm long, 0.4-0.7 mm diam. at apex, yellow,

glabrous; leaf blades 1.8-9.4 cm long, 1.3-5.3 cm wide,

ovate to elliptic-ovate, apex acute to shortly cuspidate-

acuminate, margin subentire or minutely (0.5 mm) den-

ticulate with 8-20 teeth/side, base obtuse to rounded,

thinly to stiffly chartaceous, upper surface with simple

or stellate hairs 0.2-1 mm long, lower surface stellate-

pubescent with hairs 0.3-0.6 mm wide, venation pinnate

or subpalmate, 2° veins 3-5/side. Inflorescences termi-

nal, <3 or bisexual, 2-12 cm long, proximal 2 flowers 1-

12, distal part of spike 1-1.7 cm diam., <5 flowers

1/bracteole, pedicels 2-3 mm long, slender, bracteoles

2-4 mm long, linear, often with glands. Male flower buds

2-2.5 mm diam., calyx lobes 1.5-2 mm long, triangular

to ovate, pubescent externally, petals 1.8-2.5 mm long,

spathulate to narrowly obovate; stamens 9-11, filament

2-3 mm long, glabrous, anthers 0.5-0.9 mm long. Fe-

male flowers ca. 6 mm long, calyx lobes 2.5-5 mm long,

ca. 1.3 mm wide, narrowly triangular, petals subulate or

absent, ovary globose, pubescent, styles deeply bifid.

Fruits 5.5-6 mm long, 4.5-5.5 mm diam., rounded-ob-

long, densely pubescent; seeds ca. 4.2 mm long, 2.8-3.2

mm wide, 1.5-2 mm thick, oblong, smooth, lustrous,

caruncle ca. 1.5 mm wide.

BURGER & HUFT: FLORA COSTARICENSIS

95

Plants of secondary growth in evergreen lower

montane forest formations, 1300-2100 m eleva-

tion. Flowering and fruiting collections have only

been made in June-August and November. The

species is only known from the northeastern part

of the Meseta Central, from near Grecia and Zur-

qui eastward to Cartago and Paraiso.

Croton ortholobus is recognized by its short

shrubby habit, paired stipitate yellowish glands at

the apex of the petiole (mostly abaxial side), leaf

blades often with simple hairs above and stellate

hairs beneath, very restricted geographic range,

and limited flowering period. The sharp hispid

hairs of stems and petioles are actually the central

rays of stellate hairs with much smaller basal/lat-

eral rays. The type (Friedrichsthall 1417 G, photo

F) was mislabeled as coming from Guatemala; it

was collected near Cartago. The name C. costa-

ricensis has been used for this species and also

misapplied to collections of C. jutiapensis from

lowland Guanacaste.

ca. 2 mm thick, oblong, lustrous, grayish yellow, caruncle

ca. 1 mm wide.

Uncommon plants of open sites in seasonally

very dry deciduous areas, 20-300 m elevation (0-

1 200 m in South America). Flowering and fruiting

material was collected in July ( Webster et al. 12475

F) and August ( Wilbur 31 130 F) in Costa Rica. The

species appears to range disjunctly from Oaxaca,

Mexico, and the West Indies to Colombia and

Venezuela.

Croton ovalifolius is distinguished by its small

stature, small leaves, stellate pubescence, unusual

stipules, and $ sepals. The stipules, bracteoles, and

9 sepals have a similar glabrous texture (drying

smooth and brown) that suggests succulence in life,

and all have distinctive gland-like teeth (with or

without distal knobs) along the margins. The North

American material usually has broader leaves, and

the larger seeds lack the longitudinal striations

characteristic of South American material.

Croton ovalifolius Vahl in H. West, Bidr. Beskr.

Ste. Croix 307. 1793. C. escathos Croizat, J.

Arnold Arbor. 21: 79. 1940. Figure 10.

Herbaceous subshrubs 20-90 cm tall, bisexual, leafy

stems 0.6-2 mm thick, hairs stellate, 0.5-1.5 mm wide

with slender rays or partly stellate with a single long (1-

2.3 mm) ray; stipules 1-2.5 mm long, 0.1-0.6 mm wide,

usually lacking stellate hairs and with several glandular

teeth along the margin, drying brown, caducous. Leaves

with slender petioles 2-8(-18) mm long, 0.2-0.4 mm

thick, densely stellate-pubescent, apical glands lacking;

leaf blades 9-35 mm long, 4-18 mm wide, oblong to

ovate-oblong or elliptic-oblong, apex obtuse or rounded,

margin minutely serrate with 10-20 small (0.3 m) teeth/

side, base obtuse to cuneate, drying chartaceous, sparsely

stellate-pubescent above with 6-rayed hairs, densely stel-

late-pubescent beneath with hairs 1-2 mm diam., ve-

nation subpalmate, 2° veins 3— 4/side with basal pair

prominent. Inflorescences terminal or axillary, 1-4 cm

long, bisexual or <5, stellate-pubescent throughout, with

1-3 proximal 9 flowers on slender pedicels 3-8 mm long,

$ flowers 5-15, solitary in axils of bracteoles 1-2 mm

long, with glandular margin, pedicels l-2.3(-3.5) mm

long. Male flower buds ca. 2.2 mm diam., 4-5 mm wide

at anthesis, sepals 5, 1.2-2 mm long, ca. 1 mm wide,

acute, sparsely pubescent, petals 1.5-2.5 mm long, ca.

0.7 mm wide, spathulate-oblong, glabrous except for

minute white hairs at the blunt apical margin; stamens

8-12, filaments 1.4-2 mm long, slender, glabrous, an-

thers 0.5-0.7 mm long. Female flowers 4-6 mm long,

sepals 5, 4-7 mm long, 0.5-0.7 mm wide, linear-oblong

with glandular marginal teeth 0.4-1 mm long and few

stellate hairs; ovary ca. 2 mm long, densely stellate-pu-

bescent, styles to 4 mm long. Fruits ca. 6 mm long,

oblong, 3-lobed, stellate-pubescent, columella ca. 3.5 mm

long; seeds (3-)3.6-4.8 mm long, (2.2-)2.7-3.3 mm wide,

Croton pachypodus Webster, Ann. Missouri Bot.

Gard. 75: 1119. 1988. Figure 17.

Trees 6-30 m tall, bisexual, leafy stems 1.3-4 mm

thick, with small (0.1-0.4 mm) flat appressed rounded

peltate hairs; stipules 2-4 mm long, lanceolate to su-

bulate, caducous. Leaves with petioles 10-45 mm long,

0.8-1.6 mm thick, densely covered with peltate hairs,

apex with paired lateral glands 0.4-0.8 mm long, 0.4-

0.6 mm wide distally, usually cylindrical to stipitate con-

ic (rarely absent); leaf blades 4-13 cm long, 2-6 cm wide,

elliptic to elliptic-oblong or ovate-oblong, apex bluntly

acute to short-acuminate or caudate-acuminate, margin

obscurely crenate with 5-1 5 small (0.5 mm) sinuses/side,

base obtuse to slightly rounded, drying thinly to stiffly

chartaceous, dark and glabrous above or with flat stellate

hairs, paler beneath with many small (0. 1-0.2 mm diam.)

flat peltate hairs, venation pinnate, 2° veins 5-8/side.

Inflorescences terminal (pseudoaxillary), 2-9 cm long,

racemiform, usually unisexual (bisexual inflorescences

rare, with 1 9 flower and 2-3 6 flowers in proximal cy-

mules), with peltate hairs, 9 flowers 1-7, proximal, on

pedicels 2-7 mm long; <5 flowers in groups of (l-)2-3, on

pedicels 2.5-5 mm long, covered externally with peltate

hairs, bracteoles 0.5-1 mm long. Male flowers with 5

valvate calyx lobes, 1 .2-3 mm long, triangular, petals 2-

3.2 mm long, ca. 1 mm wide, elliptic to oblanceolate,

glandular punctate, margins tomentulose, glabrous abax-

ially; stamens 10-1 3, filaments 2-4.5 mm long, glabrous,

anthers 0.6-1 mm long. Female flowers 5-7 mm long,

calyx lobes 5, 2.2-2.7 mm long, triangular or ovate, disc

ca. 2.8 mm wide, petals apparently absent; ovary 2-3

mm long, ovoid, densely yellowish with peltate hairs,

styles 2.5-3.5 mm long, distally bifid, glabrous. Fruits

3.5-5 cm long, 3—4 cm wide, obovoid, rounded to trun-

cated at apex, walls ca. 2 mm thick and woody, surfaces

covered with peltate hairs, columella 25-34 mm long;

seeds 20-29 mm long, 1 1-18 mm wide, 8-9 mm thick,

96

FIELDIANA: BOTANY

oblong in outline and slightly convex abaxially, caruncle

3 mm long, 2.5 mm wide, inverted V-shaped, appressed.

Trees of evergreen forest formations on both the

Pacific and Caribbean slopes, 300-1000 m ele-

vation. Flowering in March-June; with mature fruit

in July-October. This species ranges from Volcan

Rincon de La Vieja southward to western Panama.

Croton pachypodus is recognized by its tall stat-

ure, small but conspicuous flat peltate hairs, av-

erage-sized leaves, terminal unisexual racemes, and

very large capsules and seeds. The ovary is covered

with lustrous yellowish peltate hairs, and these

persist but become grayish on the fruits. The flat

peltate hairs have 20-50 radiating rays united for

most of their length but separated distally ( x 50).

This can give the impression of a scurfy or stellate

form in some instances. Campano is a common

name. The preceding description is based on Costa

Rican material and differs from Panamanian ma-

terial having smaller leaves that are more densely

pubescent beneath, somewhat larger fruits, and

fewer stamens/flower. Specimens placed here are

the following: Bella 1039; Gomez- Laurito 12282;

Haberetal. 4896, 7036, 7106, 7109, 8395; Ham-

mel & Grayum 18936; Herrera 607; Holdridge

6737, 6784; A. Jimenez 1953; Q. Jimenez 635 &

987; Stork 2811; and Zamora & Poveda 822. Some

of these collections were earlier misidentified as

C. tenuicaudatus (q.v.).

Croton punctatus Jacq., Coll. 1: 166. 1787. Icon.

PI. Rar. 3: 19, t. 621. 1789. Figure 17.

Small shrubs 0.3-1 m tall, bisexual, leafy stems 1.4-

4 mm thick, covered at first with short-stalked flat-topped

discoid-stellate hairs 0.3-0.5 mm wide, becoming woody

and black; stipules absent. Leaves with petioles 7-28(-

37) mm long, 0.6-1.5 mm thick, densely stellate-pubes-

cent like the stems; leaf blades 1.8-4.5 cm long, 1-2.8

cm wide, ovate-oblong to oblong, apex bluntly obtuse

to rounded, margin entire, base rounded and slightly

truncate, drying stiffly chartaceous or subcoriaceous, pale

grayish green or yellowish green and paler beneath, upper

surface with stellate hairs 0.1-0.2 mm wide, lower sur-

face with rounded stellate-edged hairs 0.3-0.8 mm wide,

venation pinnate with 4-5 veins/side but usually ob-

scure. Inflorescences terminal, bisexual, 1-4 cm long,

peduncles to 14 mm long, ca. 1 mm thick, pubescent, 9

flowers 1-2 and proximal, subsessile, pedicels to 1 mm

long in fruit; <5 flowers 4-7. Male flower buds globose,

ca. 2 mm diam., sepals 5, ca. 2.5 mm long, petals absent;

stamens 10-12, filaments to 1.5 mm long, anthers 0.8-

0.9 mm long. Female flowers ca. 4 mm long, 3.5 mm

wide at apex, sepals 5, 3-3.5 mm long, 1 .8-2.2 mm wide;

ovary with peltate hairs, styles free, 3 times bifid. Fruits

ca. 5 mm long, 8-10 mm wide, oblate and 3-lobed, densely

stellate-peltate, columella 3.8-4.2 mm long; seeds 4.5-

5.3 mm long, 3.7-4.3 mm wide, 3.2-4 mm thick, ellip-

soid to subglobose, dark to pale yellowish or mottled.

Plants of sandy Caribbean seashores, often

growing within a few meters of the high-tide mark;

0-20 m elevation. Probably flowering and fruiting

throughout the year. The species ranges from North

Carolina (U.S.A.) to Panama and is found on Cuba

and Bermuda.

Croton punctatus is distinguished by its restric-

tion to sandy Caribbean seashores, short dark

woody stems, small pale grayish oblong leaves with

entire margins, and rounded apex. The vestiture

on stems and petioles is unusual. The hairs are

short-stalked with a flat rounded top that has a

fringe of minute thin rays (resembling stellate hairs).

Because of this form the hairs have both a stellate

and peltate appearance.

Croton pungens Jacq., Coll. 4: 2 1 7. 1 79 1 . Icon. PI.

Rar. 3: 19, pi. 622. 1794. Croton standleyi Stey-

ermark, Publ. Field Mus. Nat. Hist., Bot. Ser.

22: 151. 1940. Figure 18.

Shrubs or small trees 1 .2-7(-20?) m tall, bisexual, leafy

stems 2-5 mm thick, hispidulous with scurfy-stellate hairs

0.2-0.5 mm diam. or with longer rays 0.6-1 mm long;

stipules 1-4 mm long, linear or subulate. Leaves with

petioles 3-13 cm long, 1.3-2 mm thick, stellate-scurfy

pubescent, with 2-4 stipitate conic, patelliform or dis-

coid yellowish glands near the apex; leaf blades 5-12(-

22?) cm long, 3-9(-l 3?) cm wide, ovate to ovate-oblong,

caudate-acuminate with narrow tip 5-18 mm long, mar-

gin minutely (0.3 mm) denticulate or subentire, base

rounded and cordate with sinus 3-18 mm deep, basal

lobes widely separate to overlapping, drying chartaceous,

upper surfaces with stellate hairs 0.1-0.4 mm diam.,

lower surface with stellate hairs 0.2-0.8 mm wide, ve-

nation palmate with 3 major veins, 2° veins 4-8/side of

the midvein. Inflorescences terminal (pseudoaxillary),

bisexual, 3-24 cm long, rachis ca. 1.5 mm thick and

densely stellate, proximal cymules with 9 and 3 flowers,

distal cymules with 2-5 flowers, bracteoles 1-3 mm long,

9 flowers subsessile, $ pedicels 3-4(-8) mm long. Male

flowers stellate-pubescent externally, sepals 5, 2-2.5 mm

long, 1.1-1.4 mm wide, petals 1.5-2.3 mm long, spathu-

late, puberulent only along the distal edge, receptacle

villous; stamens ca. 1 8-40, filaments 2-3 mm long, gla-

brous, anthers 0.6-0.9 mm long. Female flowers with 5

sepals 2.2-3.7 mm long, 1.5 mm wide, triangular, petals

0.3-0.4 mm long, stellate on both surfaces; ovary stellate,

styles pubescent basally, 4-5 mm long, bifid distally.

Fruits ca. 7 mm long, scurfy-stellate, columella 5-6 mm

long; seeds 5.2-6 mm long, 3.7-4.1 mm wide, ca. 3 mm

thick, rounded but with longitudinal or irregular raised

areas on adaxial side, caruncle 1.5-1.8 mm wide, round-

ed.

Plants of fields, grasslands, and open sites in

montane forest formations, 1300-2100 m eleva-

BURGER & HUFT: FLORA COSTARICENSIS

97

tion. Flowering collections have been made in Jan-

uary-February, April, and July-August. In Central

America, this species is restricted to the Chiriqui

highlands, Panama, and adjacent Costa Rica; it

ranges to Brazil.

Croton pungens is recognized by its smaller cor-

date leaves, inflorescences with proximal cymules

having both 9 and <5 flowers, many stamens, larger

seeds, and restricted occurrence in southern Cen-

tral America. The hairs of the upper leaf surface

have minute (0.1-0.2 mm) stalks and flattened

distal surfaces with ca. 12 radiating points. This

species is closely related to C. xalapensis (q.v.).

Croton schiedeanus Schldl., Linnaea 19: 243. 1847.

C. perobtusus Lundell, Phytologia 1: 405. 1940.

Figure 17.

Shrubs or small trees 3-1 5(-25?) m tall, bisexual, trunk

10-25 cm diam., leafy stems 1.3-6 mm thick, densely

covered with flat rounded peltate hairs ca. 0.2 mm diam.,

often with a brown center; stipules minute or up to 4

mm long, ca. 0.5 mm broad at base, linear, deciduous.

Leaves with petioles 6-50(-58) mm long, 0.7-1.9 mm

thick, slightly thickened at apex and base, covered with

peltate hairs, without glands at apex; leaf blades 7-19(-

29) cm long, 3-8(-l 1) cm wide, elliptic to ovate-elliptic,

narrowly elliptic-oblong or oblong, apex usually short-

acuminate with tip ca. 5-7 mm long, margin entire, base

obtuse to cuneate (rarely rounded and subtruncate), dry-

ing thinly chartaceous, dark brown to grayish brown,

sparsely or densely pubescent above (hairs sometimes

obscure), more densely pubescent beneath with flat pel-

tate hairs 0.1-0.2 mm diam., venation pinnate, 2° veins

(7-)9-l 3/side. Florescences terminal or axillary, 1-2/axil,

racemes (pseudopaniculate when distal leaves fail to de-

velop), 3-7 (-12) cm long, bisexual or 6, with 1-9 prox-

imal 9 flowers on long (8-27 mm) pedicels 0.2-0.7 mm

thick; with many distal 3 flowers solitary in axils of small

(0.5 mm) bracteoles, <5 pedicals 2-5 mm long, ca. 0.2

mm thick, pubescence of peltate hairs. Male flower buds

1.2-1.7 mm diam., 3-6 mm wide at anthesis, white,

calyx 5-parted, lobes 0.5-1.5 mm long, petals 1-3 mm

long, with minute white hairs along the edge; stamens

9-1 1, filaments 1.2-2 mm long, anthers 0.5-1 mm long.

Female flowers ca. 2-3 mm long, 3-5 mm wide, calyx

lobes 5, 1.5-3 mm long, 1-1.3 mm wide at base, tri-

angular, petals 1.5-2 mm long, broadly elliptic, white;

ovary ca. 2 x 2.3mm, covered with whitish peltate hairs,

styles branched near the base, 2-3 mm long, usually 3

times bifid. Fruits 9-13 mm long, 9-12 mm diam., ob-

long or subglobose, 3-lobed in cross-section, with flat

hairs 0.2-0.4 mm diam. and conical protuberances ca.

0.5 mm high, columella 6-9 mm long; seeds 7-9 mm

long, 4.8-6 mm wide, 2.7-4 mm thick, oblong, caruncle

0.9-2 mm wide, surface lustrous and yellowish brown

to mottled dark brown/white.

Common plants of lowland evergreen and partly

deciduous forest formations, 0-800(-1200) m el-

evation (to 1400 m in Chiriqui and adjacent Costa

Rica). Found within forests, on forest edges, and

often along streamsides. Flowering in all months,

but with a majority of collections made in Janu-

ary-March; fruiting mostly in February-April. The

species ranges from Mexico to Peru.

Croton schiedeanus is recognized by its vesture

of flat appressed-peltate hairs, lack of petiolar

glands, pinnately veined leaves, long-pedicellate 2

flowers with many style branches, and many in-

dividual 6 flowers along the slender racemose floral

axis. The flat rounded-appressed hairs often have

a brown or reddish brown center and translucent

or whitish periphery. Central American collec-

tions were called C. glabellus L. (C. nitens Sw.) for

many years, but Webster and Burch (1967, p. 250)

noted that, though closely related, the Linnaean

species is restricted to Jamaica and the Cayman

Islands. (Compare the closely related C. tenuicau-

datus, and note that small-leaved specimens of C.

schiedeanus with more rounded blades can look

very much like C. pachypodus.) This is the most

commonly collected species of Croton in Central

America; its name in Costa Rica has been recorded

as colpachi, colpalchil, copalchi, and quizarra col-

pachi.

Croton skutchii Standl., Pub. Field Mus. Nat. Hist.,

Bot. Ser. 22: 86. 1940.

Trees 10-27(?) m tall, bisexual, leafy stems 4-8 mm

thick, with flat rounded-peltate hairs 0. 1-0.3 mm diam.;

stipules minute or absent. Leaves with petioles 7-15 cm

long, 1 .4-3 mm thick, covered with minute flat or scurfy

hairs with brown centers, paired lateral/abaxial sessile

pateliform glands present at the apex, to 2 mm wide,

thickened tissue ca. 1 mm long also sometimes present

at the petiole/blade juncture; leaf blades 15-26 cm long,

10-18 cm wide, ovate-oblong to broadly oblong, or nar-

rowly ovate-oblong, apex acuminate to obtuse, margin

entire, base rounded and truncate to subcordate, drying

chartaceous, drying greenish brown above with scattered

appressed hairs (in the type) or subglabrous, pale green-

ish beneath with flat rounded hairs 0.1-0.2 mm diam.,

venation pinnate, 2° veins 1 2-1 7/side. Inflorescences ax-

illary to distal leaves, 1-2/node, bisexual, 1 5-25 cm long,

with peltate hairs throughout, with 1-5 proximal solitary

9 flowers on pedicels 6-1 1 mm long, 1-1.5 mm thick,

bracteoles subtending the $ glomerules ca. 1 mm long, <5

flowers in groups of 5-11. Male flowers only seen in

early anthesis, buds 2-3 mm diam., calyx ca. 4 mm long,

calyx lobes 1.5-2 mm long triangular, petals ca. 3 x 1

mm, narrowly obovate; stamens ca. 11, filaments 3-4

mm long, anthers 1.2x1 mm. Female flowers with sepal

lobes 4-6 mm long, 3-5 mm wide, oblong, lateral mar-

gins occasionally reflexed; ovary 2-3 mm high, 3 mm

diam., covered with lustrous peltate hairs, styles hairy

at the base, much divided, distal branches more than

20. Fruits and seeds not seen.

98

FIELDIANA: BOTANY

Plants of evergreen forest formations of the Ca-

ribbean and Pacific slopes, 600-1000 m elevation.

Flowering in June and August. The species is known

only from two collections: Skutch 4377 (us iso-

type), from near El General, San Jose Province,

and Lancaster Aug. 5, 1923 (us) from Cachi in

Cartago Province.

Croton skutchii is recognized by the flat round

appressed scales on most surfaces, the larger ob-

long leaves with many secondary veins and usually

subcordate base, and the large solitary 9 flowers

with many style branches. The large broad sepal

lobes in 9 flowers are distinctive. The flat rounded

appressed hairs often have a brown center. This

species superficially resembles C. tenuicaudatus

(q-v.).

Croton smithianus Croizat, J. Arnold Arbor. 21:

93. 1940. Figure 18.

Trees 5-25 m tall, bisexual, leafy stems 2.5-7 mm

thick, densely pubescent with sessile or stipitate stellate-

scurfy hairs 0.3-0.8 mm diam., on stalks to 1.3 mm

long; stipules 5-9 mm long, 1-2 mm broad at the base,

lanceolate, caducous. Leaves sometimes opposite at dis-

tal or flowering nodes, petioles 5-1 5 cm long, 1 .4-3 mm

thick, densely scurfy-stellate pubescent, with 2 lateral

sessile saucer-shaped or patelliform glands at the apex,

0.9-1.3 mm wide; leaf blades ll-26(-35) cm long, 8-

25(-30) cm wide, broadly ovate and usually distally tri-

lobed, the broad triangular distal lobes separated by wide

sinuses 1-5 cm deep, apex obtuse to short-acuminate,

tip to 6 mm long, margin minutely denticulate with teeth

0.1-1 mm high (rarely with broadly triangular lobes 5-

10 mm long), base rounded and cordate to subcordate,

drying thinly chartaceous, upper surface with stellate hairs

0.3-1 mm in diam., with 6-12 rays, 0.3-1 mm diam.,

on stalks 0.1-0.5 mm long, more densely pubescent be-

neath, venation palmate with 3 major veins, 2° veins 3-

5/side of the midvein. Inflorescences usually unisexual

(with 5-15 proximal bisexual cymules and distal $ cy-

mules when bisexual), 20-50 cm long, densely yellowish

pubescent, 9 flowers solitary with pedicels 5-9(-14) mm

long, ca. 1.5 mm thick $ fascicles (cymules) with 3-15

flowers, <5 pedicels 1.5-5 mm long, stellate. Male flower

buds 3-4 mm diam., calyx 3.5-4 mm long, calyx lobes

5, 2-3 mm long, triangular, petals 3-4.5 mm long, spath-

ulate, pubescent; stamens 10-12, filaments 3-4.5 mm

long, glabrous only distally, anthers 0.8-1.4 mm long.

Female flowers with 5 valvate sepal lobes, 3-7.5 mm

long, 2.5-6.5 mm wide, stellate abaxially and on mar-

gins, disk entire, ovary ca. 1.7 mm wide, styles free,

hispid, ca. 5 mm long, each style deeply multifid. Fruits

ca. 8 x 11 mm, yellowish, with scurfy and stellate hairs

0.1-0.3 mm wide, columella 4-4.5 mm long; seeds 4.7-

5.1 mm long, 3.7-3.9 mm wide, 2.8-3 mm thick, surface

with minute longitudinal raised ridges, caruncle 1.7-2.2

mm wide.

Plants of evergreen rain forest formations on

both the Caribbean and Pacific slopes, 20-800 m

elevation (to 1 500 m in Colombia). Flowering ma-

terial was collected in June-August; fruiting in

September. It is rarely collected in Costa Rica (La

Selva, General Valley, Osa Peninsula). The species

ranges from southernmost Nicaragua to Colom-

bia.

Croton smithianus is distinguished by its large

leaves with three prominent distal lobes (not pres-

ent on all leaves), stellate-scurfy pubescence with

occasional stipitate hairs, cupulate $ calyx, solitary

9 flowers with broad calyx lobes, many style

branches, and longitudinally rugulose seeds. Gla-

brous short-stalked patelliform or saucer-shaped

glands are sometimes found on the leaf surfaces

in this species. Specimens lacking the three-lobed

leaves may be mistaken for C. draco and similar

species. This species is part of a species complex

including C. palanostigma Klotzsch, C. benthami-

anus Mull. Arg., and C. killipianus Croizat (cf.

Webster & Huft, 1988).

Croton speciosus Mull. Arg., Linnaea 34: 83. 1 865.

C. speciosus subsp. tacarcunensis Webster, Ann.

Missouri Bot. Card. 75: 1119. 1988.

Shrubs or small trees 3-15 m tall, bisexual, leafy

branches 2-12 mm thick, densely villose with soft or

stiff stellate hairs 0.5-2 mm long; stipules 6-12 mm long,

0.7-2 mm wide at the base, densely villose abaxially,

entire or with laciniate margins. Leaves with petioles

1.5_15(_30) cm long, 1.5-2(-4) mm thick, densely stel-

late-villous, slender stalked glands at apex, usually 2 and

0.7 mm long or absent in ours (5-10, 5 mm long); leaf

blades 7-15(-35) cm long, 4-16(-33) cm wide, ovate to

ovate-triangular or 3-lobed in larger leaves, apex acu-

minate, margin minutely glandular dentate, rounded at

the base and subcordate to cordate, whitish beneath with

a dense tomentum of stellate hairs ca. 1 mm wide, ve-

nation palmate, 2° veins 4-9/side of the midvein. Inflo-

rescences terminal or pseudoaxillary, 2-6 cm long, bi-

sexual, few-flowered, densely pubescent, flowers solitary

or closely clustered, bracts 5-10 mm long, ca. 1 mm

wide, <5 pedicels 3-8 mm long, $ pedicels 1-3 mm long.

Male flowers ca. 8 x 12 mm, calyx lobes 3-5 mm long,

triangular, petals 4-5 mm long, obovate-spatulate, pu-

bescent abaxially, glabrous adaxially; stamens 40-70(-

80), filaments glabrous, anthers ca. 1 .5 mm long. Female

flowers densely tomentulous, calyx 5-parted, 8-16 mm

long, valvate, tapering gradually to the acute apex, petals

absent, disk inconspicuous; ovary 4-6 mm diam., dense-

ly pubescent, styles 6-9 mm long, 2 times bifid to near

the base, pubescent except at the tips. Fruits 10-14 mm

long, subglobose, hispidulous, columella ca. 8 mm long,

slender; seeds ca. 7 mm long, 5 mm wide, brown, carun-

cle 2-3 mm wide.

Rarely collected plants of evergreen forest for-

mations of the Pacific slope above Buenos Aires,

at 1500 m elevation. Flowering and fruiting in

BURGER & HUFT: FLORA COSTARICENSIS

99

March (Grayum 10265). The single collection in

Costa Rica and several collections from Cerro Ta-

carcuna in eastern Panama are the only records

for this species outside of Venezuela.

Croton speciosus is distinguished by the dense

tomentum on all parts, the large 2 flowers with

valvate sepals, and the <3 flowers with ca. 50 sta-

mens. In addition, the larger leaves have three

distal lobes with narrow acuminate apices, but the

smaller leaves are unlobed. The Costa Rican col-

lection is consistent with the description of subsp.

tacarcunensis in having smaller nonlacerate stip-

ules, and smaller glands at the apex of the petiole

than collections from Venezuela. The Costa Rican

collection has somewhat smaller leaves than typ-

ical of the species (the larger dimensions of Ven-

ezuelan material are given in parentheses in the

preceding description).

Croton sphaerocarpus H.B.K., Nov. gen. sp., 2:

84, t. 105. 1817. C. rhamnifolius var. caudatus

Pax in Pittier, Prim. Fl. Costaric. 2: 331. 1900.

Figure 16.

Shrubs l-2(-4) m tall, bisexual, leafy stems 1-3 mm

thick, at first densely pubescent with stellate hairs 0.2-

0.9 mm diam., sessile or on short (0.2 mm) stipes, some

with thin hairs to 0.8 mm long, glabrescent; stipules 2-

3 mm long, linear. Leaves with petioles 10-25(-42) mm

long, 0.4-1 .3 mm thick, stellate pubescent, glands absent

at the apex of the petiole; leaf blades 4-12 cm long, 2-

6.4 cm wide, ovate to ovate-rhombic or narrowly ovate-

elliptic, apex acuminate to caudate-acuminate, narrow

tip 6-30 mm long, margin entire (rarely with teeth ca.

0.5 mm long), base rounded or obtuse, drying membra-

naceous or thin chartaceous, dark above with simple or

stellate hairs, more densely pubescent and grayish be-

neath with hairs to 0.8 mm diam., mostly with 6-8 rays,

venation palmate or subpalmate, 2° veins 3-5/side of

midvein. Inflorescences terminal, 1.5-11 cm long, bi-

sexual, $ flowers proximal, solitary, 6 flowers in distal

cymules of 1-3, bracteoles 1.3 mm long, 6 pedicels 1.5-

3 mm long, filiform, usually glabrous. Male flower buds

ca. 2 mm diam., sparsely pubescent on the exterior, se-

pals 5, ca. 1.3 mm long, triangular and acute, petals

spathulate; stamens ca. 15, anthers 0.6-0.8 mm long.

Female flowers with sepals ca. 1 mm long, triangular,

ovary 1.5-3 mm long, 1.3-2.5 mm diam., densely his-

pidulous with hairs to 0.7 mm long, styles deeply bifid,

2.5-3 mm long, subglabrous. Fruits ca. 7.5 mm long, 6.8

mm wide, columella 4.7-5 mm long; seeds 5-5.6 mm

long, 3.7-4.2 mm wide, 2.2-2.8 mm thick, smooth, car-

uncle ca. 1.5 mm wide.

Plants of seasonally very dry deciduous wood-

lands and open rocky sites, 0-300 m elevation (to

800 m in Nicaragua). Flowering in May-July;

fruiting in June-October. It is rarely collected in

Costa Rica ( Webster & Poveda 22163, Tonduz 2766

(type of C. rhamnifolius var. caudatus), Wilbur

21442, Zamora & Chavarria 1028). The species

is found in Mexico and ranges from northern Nic-

aragua to northern Guanacaste Province, Costa

Rica.

Croton sphaerocarpus is recognized by its thin

ovate leaves often with long narrow acuminate

apices, absence of glands at the apex of the usually

long slender petiole, often slender inflorescences,

and restriction to seasonally very dry deciduous

areas. A variety of Nicaraguan collections are

placed here, ranging from specimens with short

petioles and stiffly chartaceous ovate-lanceolate

leaves to specimens with thin broadly ovate leaves

on long thin petioles. Croton morifolius Willd. of

Mexico may be an earlier name for this species;

we follow the annotations of Webster.

Croton tenuicaudatus Lundell, Phytologia 1:451.

1940. Figure 19.

Shrubs or trees to 18 m tall, bisexual, leafy stems 2-

7 mm thick, covered with peltate rounded hairs 0. 1-0.2

mm diam. and small (ca. 0.2 mm) straight hairs; stipules

minute or absent. Leaves with petioles 3-10 cm long, 1-

2 mm thick, covered with appressed flat hairs, often

thickened or geniculate at the apex; leaf blades 8-25 cm

long, 5-12 cm wide, ovate-oblong to broadly oblong,

acuminate at the apex with a narrow tip 5-15 mm long,

margin entire, base rounded and broadly obtuse to trun-

cate, usually drying dark brown above with scattered

peltate hairs, pubescent beneath with rounded peltate

hairs 0.1-0.2 mm diam., venation pinnate, 2° veins 8-

13/side. Inflorescences axillary to distal leaves or ter-

minal (pseudopaniculate when distal leaves fail to ex-

pand), 3-16 cm long, <3 or bisexual with 1-5 $ flowers

proximally, with peltate hairs throughout, 9 flowers sol-

itary, pedicels 3-7 mm long, ca. 1 mm thick; $ flowers

solitary, subtended by linear bracts to 2 mm long, ped-

icels 2-4 mm long. Male flowers ca. 7 mm wide at an-

thesis, calyx lobes ca. 3 mm long, triangular, petals 5,

3—4 mm long, narrowly obovate; stamens 10-13, fila-

ments to 4 mm long, anthers 1 .2-1 .5 mm long, narrowly

oblong. Female flowers 6-8 mm wide at anthesis, calyx

lobes 5, ca. 3 mm long, triangular, petals narrowly ob-

ovate, 3.5—4 mm long; ovary ca. 4 mm long, covered

with lustrous peltate hairs, styles 3 or 4 times bifid, gla-

brous distally. Fruits not seen (see below).

Plants of evergreen forest formations from near

sea level to 900 m elevation, Valle del General,

to Golfo Dulce. Flowering in November-March.

This species is known only from the Pacific slope

of southern Costa Rica and western Panama.

Croton tenuicaudatus is recognized by the small

flat rounded peltate hairs on all parts, the larger

leaves rounded at the base, the lack of glands at

the apex of the petiole, the solitary flowers, and

the restricted range. This species is very similar to

100

FIELDIANA: BOTANY

the common and widely ranging C. schiedeanus

(q.v.), and the two are closely related. It appears

that ascribing large seeds to this species (Webster

& Burch, 1 967, p. 253) was an error, with the result

that this name had been incorrectly used for ma-

terial now placed in C. pachypodus (q.v.).

Croton tonduzii Pax in Pittier, Prim. Fl. Costar. 2:

330. 1990. Figure 17.

Small trees ca. 6 m tall, leafy stems 1.7-5 mm thick,

young stems with appressed rounded flat peltate hairs

ca. 0.2 mm diam.; stipules ca. 1 mm long, caducous.

Leaves with petioles 3-8 cm long, 1-2.5 mm thick, cov-

ered with peltate hairs, apex with 2(-4) adaxial sessile

cupulate or patelliform glands 0.7-1.3 mm diam.; leaf

blades 9-18 cm long, 3-9 cm wide, broadly ovate (in

Pittier 3474) to ovate-oblong or oblong (in Pittier 3878),

apex bluntly acute to obtuse, margin conspicuously den-

tate-crenate with teeth 0.5-2 mm high, ca. 3 teeth/cm,

drying thinly chartaceous, dark brown above and gla-

brescent, paler beneath with many appressed flat round-

ed hairs ca. 0.2 mm diam., venation palmate (Pittier

3474) or subpalmate (Pittier 3878), 2° veins 4-8/side.

Inflorescences terminal, apparently unisexual, becoming

15 cm long with rachis 2 mm thick, hairs peltate; $

flowers not seen; 9 flowers solitary on short (1-2 mm)

thick (1 mm) pedicels, calyx ca. 2 mm long, lobes 0.7

mm long; ovary ca. 1.5 mm high and 2 mm diam.,

pubescent. Fruits ca. 7 x 9 mm, oblate, with rounded

lobes, stellate-peltate, columella 6-7 mm long; seeds 5.5-

6 mm long, 4.5-4.8 mm wide, 3.5-4 mm thick, pale

brown, lustrous and minutely rugose.

Plants of evergreen forest formations on the Pa-

cific slope between 400 and 800 m elevation.

Flowering and fruiting in January-February.

Known from only four collections: Pittier 3474,

3878 (syntypes), & 12161 and Skutch 4027. En-

demic to southern Costa Rica (but see below).

Croton tonduzii is recognized by the peltate hairs,

leaves with palmate or subpalmate venation and

denticulate margin, long petioles, and restricted

habitat. This poorly known species appears to be

related to C. pachypodus, which has much larger

fruits and seeds, and to C. mexicanus, where the

hairs are not so clearly flat and peltate. Croton

lundellii Standl. of northern Central America may

be conspecific. This species resembles C. niveus

and C. schiedeanus and, like them, is called co-

palchi.

Croton trinitatis Millsp., Publ. Field Mus. Nat.

Hist., Bot. Ser. 2: 57. 1900. C. tragioides Blake,

Contr. U.S. Natl. Herb. 24: 12. 1922. Figure 10.

Herbs or subshrubs 0.3-0.9(-1.5) m tall, bisexual, of-

ten with many widely branching stems, leafy stems 0.6-

4 mm thick, sparsely to densely pubescent with stellate

hairs 0.3-1 mm long, each hair often with many short

radiating rays and 1 slightly longer central ray; stipules

0.4-1.2 mm long, linear. Leaves sometimes subopposite

at branching nodes, petioles (l-)3-35 mm long, 0.3-0.8

mm thick, stellate-pubescent, usually with stalked cu-

pulate glabrous glands 0.4-0.8 mm long at the apex; leaf

blades 1-6 cm long, 0.6-3.5 cm wide, triangular to ob-

long or ovate in outline with prominently dentate mar-

gin, teeth 5-12/side, 1-5 mm long and 2-6 mm wide,

base of blade rounded to truncate (subcordate), drying

membranaceous or thinly chartaceous, greenish or gray-

ish brown, sparsely pubescent above with mostly simple

hairs to 1 .2 mm long, more densely pubescent beneath

with stellate hairs ca. 0.3 mm wide, venation subpalmate

with 3 (5) major veins from near the base. Inflorescences

terminal or pseudoaxillary, 3-1 5 mm long, few-flowered,

spicate or branched, stellate-pubescent, with 1-3 prox-

imal 2 flowers, the 3-8 distal $ flowers borne on slender

glabrous pedicels ca. 1 mm long, 2 pedicels to 3 mm long

in fruit. Male flowers globose in bud, ca. 0.7 mm diam.,

ca. 1.5 mm wide at anthesis, sepals 5, ca. 0.8 mm long,

petals 0.6-0.9 mm long; stamens 8-10, filaments to 1

mm long, glabrous, anthers 0.3-0.4 mm long. Female

flowers 3-5 mm long, sepals 5, 3-4 mm long, 0.8-1.7

mm wide, narrowly oblong to spathulate, petals 0.3-0.4

mm long, subulate; styles 0.7-1 . 1 mm long, bifid. Fruits

4-4.5 mm long, 3.5-4 mm diam., oblong, stellate-pu-

bescent, columella ca. 3 mm long; seeds 3-3.5 mm long,

2.2-2.5 mm wide, ca. 1.2 mm thick, oblong, with a lus-

trous usually dark minutely reticulate surface, caruncle

1.1-1.3 mm wide.

Plants of open early secondary vegetation in ev-

ergreen forest formations on both the Caribbean

and Pacific slopes, 0-1 100 m elevation. Flowering

in April-September; fruiting in April-February.

This species ranges from eastern Mexico to Peru.

Croton trinitatis is recognized by its short her-

baceous habit, distinctive narrowly triangular

leaves with prominent teeth, short few-flowered

inflorescences, and the stipitate glands at the apex

of the petiole.

Croton xalapensis H.B.K., Nov. gen. sp. 2: 85.

1817. C. pseudoxalapensis Croizat, J. Arnold

Arbor. 21: 85. 1940. C. pseudoxalapensis var.

cobanensis Croizat, J. Arnold Arbor. 21: 86.

1940. Figure 18.

Shrubs or small trees 2-1 5 m tall, bisexual, leafy stems

2-7 mm thick, densely white or yellowish hispidulous

with scurfy-stellate hairs 0.3-0.5 mm diam. and often

with thin simple hairs to 1.5 mm long; stipules 2-5 mm

long, linear, caducous. Leaves with petioles 1.5-14 cm

long, 1-3 mm thick, densely stellate-hispidulous, with 2

(3-7) usually stipitate and conical or sessile saucer-shaped

glands 0.6-2.3 mm long, 0.6-0.9 mm diam. at apex; leaf

blades 5-24(-32) cm long, 2-14(-20) cm wide, ovate to

narrowly ovate-oblong, apex long-acuminate to caudate-

acuminate, margin minutely (0.3-1.5) denticulate or

subentire, base rounded and truncate or shallowly cor-

BURGER & HUFT: FLORA COSTARICENSIS

101

date (obtuse), drying thinly chartaceous, with scattered

small (0.2-0.4 mm) stellate hairs above, more densely

pubescent beneath with somewhat larger hairs, venation

subpalmate or pinnate, basal secondaries usually prom-

inent, 2° veins 5-10/side. Inflorescences 5-25(-40) cm

long, unisexual or bisexual, spicate, densely stellate pu-

bescent, 9 flowers solitary, not associated with <5 flowers,

subsessile; 6 flowers solitary or in glomerules of 2-7,

pedicels to 8 mm long, bracteoles to 4 mm long. Male

flowers ca. 6 mm wide at anthesis, calyx 2.5-3.5 mm

long, sepals 5, 1.5-2.3 mm long, 1.5-2 mm wide, tri-

angular, petals ca. 3 x l .2 mm; stamens 1 8-3 1 (in Costa

Rica), filaments 1.8-4 mm long, glabrous distally, an-

thers 0.5-1 mm long. Female flowers with sepals 1.5-4

mm long, ca. 1.3 mm wide at base, up to 7 x 3 mm in

fruit; ovary 2-3 mm long, 3-4 mm diam., densely stel-

late-hispidulous, styles 2.3-3.5 mm long, bifid from near

the base. Fruits 6-7 mm long, ca. 7-9 mm wide, stellate-

pubescent, columella 5-6 mm long, ca. 2 mm wide at

apex; seeds 4.8-5.7 mm long, 3.7—4.4 mm wide, ca. 3.7

mm thick, with raised transverse-angular areas on both

adaxial and abaxial surfaces, caruncle ca. 2 mm wide.

Plants of montane evergreen and partly decid-

uous forest formations, 700-2100 m elevation.

Probably flowering and fruiting throughout the year

but collected most often in February-September.

The species ranges from Veracruz, Mexico, to the

central highlands of Costa Rica (and to 83°03'W

on the Caribbean slope of the Talamanca moun-

tains).

Croton xalapensis is recognized by its often larg-

er ovate-oblong leaves truncate or subcordate at

the base, stipitate glands near the apex of the pet-

iole (not always present), dense pubescence of stel-

late hairs, $ flowers with 14-33 stamens, and seeds

with transverse-oblique raised areas. Leaf vena-

tion is generally pinnate, unlike most of our other

large-leaved Croton species. The larger hairs are

distinctive in being slightly (0. 1-0.2 mm) stipitate

and having 8-24(-many) short rays, often giving

a somewhat scurfy appearance. This species has

been called targud, targud bianco, and terre in Cos-

ta Rica. This species is closely related to C. pun-

gens of the Chiriqui Highlands. Compare also C.

draco and C. hoffmannii,

Croton yucatanensis Lundell, Phytologia 1: 408.

1940. Figure 16.

Shrubs 2-3 m tall (rarely to 7 m), bisexual, leafy stems

1^4 mm thick, densely whitish stellate-tomentulose in

early stages, hairs stellate or stellate-peltate with a small

(0.1-0.2 mm) flat central area; stipules often broader

than long and leaf-like (sometimes absent or minute and

linear), 3-8 mm long, to 14 mm wide and reniform,

caducous or persisting. Leaves with petioles 5-32 mm

long, 0.6-2 mm thick, whitish with stellate hairs, small

(0.3 mm) sessile glands or stipels usually present at the

adaxial apex; leaf blades 2-1 1(-13) cm long, 1.5-5(-7)

cm wide, ovate-oblong, ovate-lanceolate, lanceolate or

ovate-oblong, apex bluntly obtuse to acuminate, margin

entire to subentire, base obtuse to rounded and subcor-

date, drying chartaceous and dark above, whitish be-

neath with a dense tomentum of stellate hairs 0.1-0.3

mm wide, venation palmate or subpalmate, 2° veins 2-

6/side of the midvein. Inflorescences terminal, 1-2, 3-

1 5 cm long, bisexual or unisexual, with whitish stellate

hairs throughout, flowers solitary, $ bracts ca. 0.7 mm

long, pedicels 3-4 mm long; $ bracts 1-2 mm long, 2

pedicels to 6 mm long in fruit. Male flowers ca. 4 mm

wide, calyx lobes 5, 1.7-2 mm long, acute, petals nar-

rowly oblong; stamens ca. 1 5, 3-4 mm long, anthers 0.7-

1 mm long. Female flowers 3-6 mm long, calyx lobes 5,

2-5 mm long, 3 mm wide at base, broad and often with

lateral margins reflexed, disk adnate to base of perianth,

ovary ca. 2.7 mm long, styles 2-4 mm long, bifid at the

base and also bifid distally (ca. 1 2 style branches/flower),

densely pubescent in lower part. Fruits 5-6 mm long, 6-

7 mm wide, oblate, sparsely stellate-puberulent, colu-

mella ca. 3 mm long; seeds 3.8—4 mm long, 3-3.2 mm

wide, 2.2-2.4 mm thick, slightly rugose with minute lon-

gitudinal ridges on abaxial surface, caruncle 0.7-0.8 mm

wide.

Plants of deciduous forest formations of north-

western Guanacaste Province (Santa Rosa N.P.

and vicinity), 0-300 m elevation (400-600 m in

Nicaragua). Flowering in May-June; probably

fruiting in July-August. This species ranges from

southern Mexico to northwestern Costa Rica.

Croton yucatanensis is easily identified by its

broadly rounded leaf-like stipules, but these may

not be present in all collections and are often ca-

ducous. The white stellate pubescence of some-

what flattened/peltate hairs, short stature, and

broad often reflexed 2 calyx lobes are additional

distinctions. The ca. 24-32 peripheral rays of the

hair are united laterally only near the center ( x 50).

Our collections were earlier identified as C. wat-

sonii Standl., a similar species of Mexico. See the

discussion under the following species.

Croton sp. aff. C. yucatanensis Lundell, Phytologia

1: 408. 1940. Figure 16.

Small trees 3-10 m tall, bisexual, leafy branchlets 1.3-

3.7 mm thick, densely stellate-tomentulose with whitish

hairs; stipules absent or minute (sometimes 1.5-4 mm

long near the inflorescences). Leaves with petioles 1 1-

45 mm long, 0.8-1.4 mm thick, whitish stellate-tomen-

tulose, glands absent or with minute glands on adjacent

lamina margin; leaf blades 2.5-12 cm long, 1.8-5.5 cm

wide, ovate to ovate-oblong or ovate-elliptic, apex acute

to acuminate, margin subentire, base obtuse to rounded

and subcordate, drying chartaceous and dark above with

scattered minute (0. 1-0.2 mm) stellate hairs, bright whit-

ish beneath with appressed stellate hairs, venation pal-

mate or subpalmate, 2° veins 3-6/side of 1° vein. Inflo-

rescences 5-17 cm long, terminal or axillary to distal

102

FIELDIANA: BOTANY

leaves, usually solitary, bisexual with many proximal 9

flowers and distal <3 flowers, solitary or crowded, rachis

1-2 mm thick, densely whitish stellate-tomentulose, 6

pedicels 3-6 mm long, ca. 0.5 mm thick, 9 pedicels 2-6

mm long, ca. 1 mm thick. Male flowers ca. 6 mm wide,

sepal lobes 5, 2.5-3 mm long, 2-2.5 mm wide, triangular,

obtuse, petals 3.5-4 mm long, ca. 1.5 mm wide, oblong;

stamens 11-14, filaments 3-4 mm long, anthers 1-1.4

mm long. Female flowers 5-8 mm long, calyx lobes 3-

6 mm long, 1.8-4 mm wide, oblong-obovate, apex

rounded or obtuse, lateral margins sometimes reflexed;

ovary 3-4 mm long, densely tomentulose, styles densely

puberulent, with 1 5-40 distal style branches/flower. Fruits

ca. 6 mm long, 3.4-3.6 mm wide, 2.6-3 mm thick, sur-

face smooth, caruncle 1.5-2 mm wide.

Small trees of deciduous and partly deciduous

forest on the seasonally dry Pacific slope of the

Cordillera de Tilaran, 700-1100 m elevation.

Flowering in June-July; fruiting in July. Collec-

tions placed here are Bella 2912 and Haber et al.

1777, 9944, 9986, 10734, & 10735. These were

collected in the upper Rio Lagarto and Rio Luis

drainages below Monteverde, near the border of

Guanacaste and Puntarenas provinces.

Croton sp. aff. C. yucatanensis is recognized by

its restricted habitat, bright white stellate hairs

covering the lower leaf surfaces and inflorescences,

the broadly reflexed 9 sepal lobes, and the many

style branches. While very similar in overall ap-

pearance to C. yucatanensis, the material placed

here differs in lacking the expanded stipules, hav-

ing fewer stamens, more divided style branches,

and larger seeds. The tree habit and higher ele-

vation habitat also separate the two. This material

keys to section Lasiogyne (Klotzsch) Bullion in

Webster's recent review (Webster, 1993) and is

also related to C. tabascensis Lundell, which rang-

es from Mexico to Nicaragua. Croton tabascensis

differs from our material in having 15-16 stamens

per flower, slender subglabrous style branches only

twice bifid, and leaves with the pubescence less

dense beneath. It is possible that all these taxa are

actually part of a single polymorphic complex.

Croton sp. A.

Small tree ca. 9 m tall, bisexual, leafy stems 1-4 mm

thick, stellate-pubescent with flat hairs 0.3-0.4 mm diam.;

stipules ca. 3 mm long, linear, caducous. Leaves subop-

posite at some nodes, petioles 3-9.5 cm long, 1-2 mm

thick, stellate-pubescent, apex with paired lateral sub-

sessile cupulate glands 0.3-0.6 mm diam.; leaf blades 9-

20 cm long, 3-9 cm wide, ovate-elliptic to lanceolate or

oblong, apex long-acuminate with narrowed tip to 20

mm long, margin subentire or with few teeth to 3 mm

high, base obtuse, drying membranaceous and dark above

with scattered stellate hairs, stellate hairs on lower sur-

face 0.5-1 mm diam. and evenly spaced, hairs flat with

usually 7 slender rays, small (0.2 mm diam.) stalked

glands present near vein axils, venation pinnate (sub-

palmate), 2° veins 4-7/side, loop-connected in the distal

part of the lamina. Inflorescences terminal or pseudoax-

illary, ca. 15 cm long, apparently bisexual, rachis 0.7-1

mm thick, stellate-pubescent, $ flowers in small glom-

erules of 1-4, bracts inconspicuous (ca. 0.5 mm); 9 flow-

ers not seen. Male flower buds ca. 2 mm diam., sepals

valvate, petals ca. 3 mm long, oblong-obovate; stamens

16, filaments glabrous, anthers 0.8-1 mm long, 0.6-0.9

mm wide. Fruits not seen, persisting pedicel 5 mm long,

1.5 mm thick, columella 1 1 mm long, 1.5 mm wide at

apex.

Croton sp. A is distinguished by its unusual

leaves, which are thin-textured, borne on long pet-

ioles, and have pinnate venation and long-acu-

minate apices. In addition, lower leaf surfaces have

flat stellate hairs with fewer than 1 0 rays and small

stalked glands near the axils of both 2° and 3° veins.

The leaves are aromatic when crushed. This un-

usual species is known only from a single collec-

tion: Gonzalez, Poveda, & Barquero 196 (MO), made

on 10 October 1992 near the Rio Corinto

(10°11'55"N, 83°53'20"W) at 250 m in a Carib-

bean rain forest (premontane wet forest) forma-

tion. This species is being studied by its discoverer,

Jose Gonzalez, who has found three trees in the

only known population.

Dalechampia Linnaeus

REFERENCES— G. L. Webster & W. S. Armbrus-

ter, A synopsis of Neotropical Dalechampia (Eu-

phorbiaceae). Dot. J. Linn. Soc. 105: 137-177.

1991. W. S. Armbruster, A new species, section

and synopsis of Dalechampia (Euphorbiaceae) from

Costa Rica. Syst. Bot. 13: 303-312. 1988.

Vines or lianas, rarely subshrubs or small erect few-

branched shrubs, monoecious, pubescence of simple uni-

cellular hairs, specialized stinging hairs present in some

species; stipules free, lateral, acute, often with parallel

venation, persisting or caducous. Leaves alternate, sim-

ple or palmately compound, often variable on the same

plant with distal leaves more lobed or divided, usually

petiolate, often with a pair of stipel-like glands at the

base of the blade, blades entire to dentate or deeply

lobed, venation palmate or pinnate. Inflorescences ax-

illary or terminal, usually solitary, bisexual, often borne

on axillary stems with reduced leaves, flower-like pseu-

danthia with 2 large subopposite usually colorful invo-

lucral bracts, palmately veined, margin entire to dentate

or laciniate, the 2 involucral bracts subtended by 4 small

involucral stipules. Male cymules with various arrange-

ments (mostly a pleiochasium of several 1-3-flowered

cymules), usually with a pedunculate 2-lipped involucel

BURGER & HUFT: FLORA COSTARICENSIS

103

with a row of stamens facing the 9 cymule and a sticky

resiniferous gland facing the upper involucral bract (in-

volucel of 2 alternate decussate bracts in some species).

Male flowers mostly 8-12, with articulated pedicels, ca-

lyx globose in bud and splitting into 3-6 valvate parts,

becoming reflexed, disk and petals absent; stamens most-

ly 20-50 (8-1 00+), filaments connate in a stiff column,

filaments very short, anthers bilocular, dehiscing longi-

tudinally; pistillode absent. Female cymules inserted

above the lower involucral bract and below the <5 flowers,

2 cymes usually with 3 flowers (1 in D.ficifolld), $ flowers

subtended by an involucel of 1 lower (proximal) bract

and 2 distal bracteoles or a single 2-lipped involucel

formed by fused bracteoles. Female flowers subsessile or

pedicellate, sepals 5-12, imbricate, mostly pinnatifid with

gland-tipped lobes in Neotropical species, expanding in

fruit, petals, staminodes and disk absent; ovary 3-

(4-)locular, ovules 1/locule, styles united to form a col-

umn, often expanded into a peltate stigma (style branch-

es absent). Fruits capsules, splitting explosively into 3

(4) 2-valved cocci, endocarp crustaceous or woody, often

developing stiff sharp hairs on the surface, columella

persisting; seeds subglobose to ellipsoid, sui faces smooth

to tuberculate, ecarunculate, endosperm present, coty-

ledons broad.

A genus of 95 Neotropical and ca. 20 Old World

species. The inflorescence is very unusual and

functions like a large individual bisexual flower,

usually held vertically with the 9 flowers below the

6. The large pulviniform nectary is interpreted to

be a modification of bracteoles of undeveloped <5

cymules. (For a recent study of these unique in-

florescences, see H. Froebe & N. Magii, Pattern

analysis in the inflorescences of Dalechampia L.,

Bot. Jahrb. Syst. 115: 27^4, 1993.) Inflorescences

of the same species can differ greatly in appearance

during different stages of flowering and fruiting,

and this can make identification quite difficult.

Neotropical species are largely pollinated by 2 bees

gathering resin from the large gland or by <5 euglos-

sine bees gathering aromas. Most species are not

well represented in herbaria, but it is difficult to

determine whether this is due to the difficulty of

discerning vining plants, the rarity of the species,

or the stinging pubescence in some species.

Key to the Species of Dalechampia

la. Plants erect shrubs 0.5-1.5 m tall, central stem usually without lateral branches; leaves simple

with pinnate venation, oblanceolate or narrowly elliptic-obovate, to 28 cm long; gland of <? involucel

yellow and lacking resin; seeds minutely tuberculate D. spathulata

Ib. Plants climbing or clambering vines and lianas, lateral branches frequent; leaves simple with

palmate venation and never oblanceolate, or compound and 3-foliolate; gland of <5 involucel absent

or producing clear, white, or maroon resin; seeds smooth or minutely rugulose 2

2a. Compound leaves with independent leaflets present, simple or lobed leaves sometimes also present

3

2b. Compound leaves absent, leaves sometimes deeply 3-lobed but the lobes not narrowed into basal

petiolules 5

3a. Trifoliolate leaves and simple ovate leaves often intermixed on stems; hairs of stems often

clearly retrorse [9 sepals 7-11; seeds 3.5-4.2 mm diam., involucral stipules 2-3 mm long]

D. heteromorpha

3b. Trifoliolate and simple ovate leaves rarely intermixed along the stems; larger stem hairs erect

and the smaller often retrorse 4

4a. Female sepals 7-11; seeds 2.8—4.2 mm diam.; involucral stipules 2-5 mm long, involucral

bracts greenish at anthesis; 400-1 100 m elevation D. cissifolia

4b. Female sepals 6; seeds 4—5 mm diam., involucral stipules 10-14 mm long; involucral bracts

greenish or white at anthesis; 0-400 m elevation D. websteri

5a. Stems, leaves, and bracts hirsute or lanate with orange or yellow-orange hairs to 2 mm long; larger

leaves usually more than 15 cm long, 3-lobed and unlobed leaves often present on same plant; $

involucel with 4 free bracteoles, glandular-laciniate [evergreen lowlands to 200 m elevation] . . 6

5b. Stems, leaves, and bracts not densely hirsute with yellow-orange hairs, hairs rarely exceeding 1

mm; larger leaves rarely > 15 cm long, 3-lobed and unlobed leaves not usually present on the

same plant (except D. tiliifolia); $ involucel with free or united bracteoles but not glandular-laciniate

7

6a. Male flowers usually 13; stigmas ca. 2 mm wide, distinct resin gland absent; margin of leaf

blades minutely denticulate; Caribbean lowlands D. shankii

6b. Male flowers usually 10; stigmas 2—4 mm wide, distinct gland with white resin present;

margins of leaf blades entire or obscurely denticulate; Osa Peninsula D. osana

104

FIELDIANA: BOTANY

7a. Leaves ovate, consistently without lobes, deeply cordate at the base; involucral bracts deciduous

before fruits become mature; 6 involucel of 4 free bracteoles 8

7b. Leaves usually deeply 3-lobed, occasionally ovate; involucral bracts often persisting as fruits de-

velop; 6 involucel with bracteoles united near base or throughout 10

8a. Fruiting sepals ca. 4 mm wide, unlobed and with laciniate margins; seeds 4-4.5 mm diam.;

stipules 6-12 mm long; stems and leaves sparsely hirsute with hairs 1-2 mm long [rare in

Costa Rica] D. canescens

8b. Fruiting sepals narrow (ca. 1 mm) with slender lateral pinnatifid lobes 1-8 mm long; stipules

2-7 mm long; stems and leaves lacking longer (1-2 mm) hairs 9

9a. Pinnatifid lobes of the fruiting sepals 4-12 mm long; seeds 4.8-5.8 mm long and with 3

longitudinal ribs; leaves usually broadly ovate D. dioscoreifolia

9b. Pinnatifid lobes of fruiting sepals 1-2 mm long; seeds 2.8—4.2 mm long, subglobose with

smooth surface; leaves usually narrowly ovate D. cissifolia

lOa. Leaves usually deeply 3-lobed, never 3-foliolate; from both deciduous and evergreen formations

on the Pacific slope (in Costa Rica) 11

lOb. Leaves usually ovate and unlobed (sometimes 3-foliolate in D. heteromorphd); from evergreen or

partly deciduous formations on both Pacific and Caribbean slopes 12

1 la. Involucral bracts with 3 short distal lobes (< % length of bract); $ bracteoles free for ca. '/2

their length; seeds 4-5 mm diam.; evergreen or partly deciduous areas, 0-500 m

D. tiliifolia

1 Ib. Involucral bracts with 3 lobes lA-l/2 the length of the bract; $ bracteoles united into a cup-

like or bilabiate structure; seeds 3.6—4.2 mm diam.; deciduous or evergreen areas, 0-1000

m D. scandens

12a. Leaf base with a usually shallow (0-1 cm) sinus, leaves narrowly ovate-triangular and unlobed or

sometimes 2-lobed; involucral bracts with 5 main veins from base, deeply 3-lobed to unlobed,

green as the leaves; evergreen or partly deciduous formations of the Pacific slope, 0-1100 m

elevation D. heteromorpha

12b. Leaf base with a conspicuous basal sinus 1-2 cm deep, leaves ovate and unlobed; involucral bracts

with 7-9 main veins, distally 5-lobed, pale green; evergreen Caribbean slopes ca. 500 m

. D. arenalensis

Dalechampia arenalensis Armbruster, Syst. Bot.

9: 275. 1984.

Clambering vines, stems 0.5-1 mm thick distally, pu-

bescence of strigose hairs 0.5-0.8 mm long; stipules 8-

10 mm long, 2-4 mm wide, lanceolate, weakly parallel-

veined, persisting. Leaves simple, petioles 1-6 cm long,

0.8-1.2 mm thick, pubescent as the stem, stipels 2 at

base of blade, 1-2 mm long, 0.8-1.2 mm wide, gland-

tipped and with 1-2 marginal glands; leaf blades 6-14

cm long, 3-8 cm wide, ovate to broadly ovate, apex

acuminate, margin entire to glandular-sinuate, base cor-

date, sinus 1-2 cm deep, drying chartaceous, surfaces

strigulose, venation palmate with 3-5 major veins. In-

florescences borne on axillary shoots 5-25 cm long, pe-

duncles 3-4 cm long at anthesis (to 6 cm in fruit), in-

volucral stipules 3-8 mm long, 1.5-2 mm wide; invo-

lucral bracts subequal, 3-4.5 cm long, 2.5-3.5 cm wide,

broadly ovate, 5-lobed distally, middle lobe 1.8-2.5 cm

long, rounded-subcordate at base, palmately 7-9-veined,

margins glandular dentate, pale green; resin gland 26-

38 mm long. Male cy mules with peduncles 3-5 mm long,

1.5-2.5 mm thick, involucel shallowly 2-lipped, lower

lip (subtending $ flowers) ca. 5 mm long, 8-10 mm wide,

margin deeply undulate, upper lip subentire; 3 flowers

10(1 terminal with 3 lateral 3-flowered groups), with ca.

20 small (2-3 mm) resiniferous bracteoles; <3 pedicels 5-

7 mm long, calyx splitting into 5-6 ovate parts, 2-3 mm

long, ca. 2 mm wide, reflexed, staminal column 3-4 mm

long, 0.7-1.5 mm thick, anthers (13-) 18-30, filaments

ca. 0.5 mm long, anthers ca. 1.5 mm long. Female cy-

mules sessile, involucel of 2 bracteoles, 4-8 mm long,

adaxial bracteole 12-15 mm wide, abaxial 4—7 mm wide;

2 flowers subsessile at anthesis, sepals usually 1 2 on cen-

tral flower and 9-10 on lateral flowers, 1-1.5 mm wide,

with laciniate eglandular teeth, ovary ca. 1.5 mm diam.,

stylar column 13-16 mm long, curving upward, ca. 1.2

mm thick, tip slightly discoid. Fruits 10-12 mm diam.,

borne on pedicels 10-20 mm long, fruiting sepals 15-20

mm long, linear, with gland-tipped teeth along margin,

sharp hairs 1-2 mm long; seeds ca. 4 mm diam., globose,

minutely rugulose, mottled brown.

Plants of evergreen Caribbean rain forest for-

mations, 300-500 m elevation. Flowering in Jan-

uary and August. Known only from the following

collections Armbruster & Herzig 79-215 DAV (type)

and Lent 2766 MO, both from the northern slopes

of Volcan Arenal in north-central Costa Rica.

Dalechampia arenalensis is recognized by its

simple ovate leaves with narrow basal sinus, in-

BURGER & HUFT: FLORA COSTARICENSIS

105

volucral bracts green at anthesis, yellow floral res-

in, and restricted range.

Dalechampia canescens H.B.K., Nov. gen. sp. 2:

98. 1817. D. friedrichsthalii Mull. Arg., Flora

55: 45. 1872. D. canescens ssp. friedrichsthalii

(Mull. Arg.) Webster & Huft, Ann. Missouri Hot.

Gard. 75: 1109. 1988.

Climbing vines, leafy stems ca. 2 mm thick, minutely

puberulent and with few straight longer hairs to 1.5 mm

long; stipules 6-12 mm long, 2-3 mm wide at base,

lanceolate, pubescent, venation parallel, reflexed and

persisting. Leaves simple, petioles 5.5-9.5 cm long, pu-

bescent as the stems, stipels 1.8-3 mm long, lanceolate,

glandular at the base; leaf blades 7-14 cm long, 5-10 cm

wide, ovate to triangular-ovate, apex abruptly short-acu-

minate, margin subentire or minutely denticulate, base

deeply cordate with lobes often overlapping, drying char-

taceous, sparsely hirsute above, minutely puberulent be-

neath, venation palmate with 3 major ascending veins.

Inflorescences axillary to leaves, solitary, peduncles (in-

cluding axillary stem with caducous leaf) 7-10 cm long,

involucral stipules 12-13 mm long, 3.5-5 mm wide,

pubescent and hispid-ciliate, parallel-veined; involucral

bracts white with green veins, ca. 3 cm long, ovate, with

3 short distal lobes, middle lobe ca. 8-9 mm long, acu-

minate, margins lacerate, 5-veined at base with petiole

1.5-2 mm long. Male cy mules with thick peduncle 1.5-

2 mm long, involucel of 4 bracts, 4-5 mm long, 7-8 mm

wide, broadly imbricate; <5 flowers ca. 10, pedicels 2-3

mm long, articulate near apex, buds 1.5-2.5 mm diam.,

sepals 4-5, stamina! column 1.3-2 mm long, hispidu-

lous, anthers (18-)2 5-3 3. Female cymules with 2 adaxial

bracteoles 5-5.5 mm long, abaxial bracteole ca. 4.5 x 6

mm, broadly ovate or reniform, crenate-toothed; 2 flow-

ers with 5-8 sepals, 1.7-2.2 mm long at anthesis, ovate-

oblong, margin fimbriate; ovary deeply 3-lobed, mi-

nutely hispidulous, styles 9-10 mm long, stigma 1-1.5

mm wide. Fruits ca. 7 mm long, ca. 9 mm wide, sub-

tended by the persisting involucral stipules and narrow

sepals to 12-15 mm long and 4 mm wide, margins la-

ciniate; seeds 4-4.5 mm diam., subglobose, slightly ru-

gose-costate.

Rarely collected plants of evergreen lowland for-

est formations. The species ranges from the Rio

San Juan, Nicaragua (Friedrichsthal 683, o type

of D. friedrichsthalii, not from Guatemala as ear-

lier described) to Peru.

Dalechampia canescens is recognized by the

simple ovate-triangular leaves with conspicuous

narrow basal sinus, the broader parallel- veined in-

volucral stipules, the lanceolate laciniate sepals

subtending the fruits, and the slightly rugose seeds

with weakly developed longitudinal costa. The

above description is based on earlier descriptions:

we have seen no material from Costa Rica.

Dalechampia cissifolia Poeppig in Poeppig & Endl.,

Nov. gen. sp. pi. 3: 20. 1845. D. trifolia Lam.,

var. cissijlora (Poeppig) Mull. Arg. in DC, Prodr.

15 (2): 1239. 1866. D. panamensis Pax & K.

Hoffm., Pflanzenreich IV, 147, XII: 19. 1919.

D. cissifolia ssp. panamensis (Pax & K. Hoffm.)

Webster, Ann. Missouri Bot. Gard. 54: 193.

1967. Figure 4.

Climbing vines, leafy stems 0.7-3.5 mm thick, pu-

bescent with thin whitish retrorse hairs 0. 1-0.5 mm long,

with few to many longer erect hairs to 2 mm; stipules

2-6 mm long, 0.3-0.7 mm wide at base, lanceolate to

linear, reflexed. Leaves 3-foliolate (rarely 5-foliolate or

simple), petioles 1.5-8 cm long, 0.5-1.3 mm thick, pu-

bescent, stipels 2, 1-3.5 mm long, 0.4 mm wide, glan-

dular at base, petiolules of central leaflet 1-6 mm long;

leaflet blades (middle leaflets) 4-1 1 cm long, 1.1-3.5 cm

wide, narrowly elliptic-oblong to narrowly ovate-elliptic,

apex acute to acuminate, margins subentire or with 2-5

short (0.5 mm) teeth/cm, base acute, lateral leaflets

asymmetric at base with a rounded-truncate side and

cuneate side, drying thinly chartaceous, sparsely and mi-

nutely (0.1-0.2 mm) puberulent on the veins beneath,

larger (0.4-0.7 mm) hairs sometime present on the sur-

faces, venation pinnate, 2° veins 5-7/side, 3° veins sub-

parallel. Inflorescences axillary (short shoots to 5 mm

long), peduncles 6-18 mm long (to 25 mm in fruit), 0.3-

0.6 mm thick, pubescent, involucral stipules 2-5 mm

long, 0.7-1 .7 mm wide at base, subulate, involucral bracts

8-18 mm long, 9-23 mm wide, to 25 x 29 mm in fruit,

broadly ovate and 3-lobed or unlobed, middle lobe 3-8

mm long, margin with short (0.5 mm) teeth, greenish.

Male cymules subsessile, involucel 1.5-2 mm long, 5-8

mm wide, reniform, pedicels 2-3 mm long; $ flowers 8-

9, buds 1.5-2 mm diam., calyx lobes 4-5, staminal col-

umn ca. 1 mm long, anthers 20-36. Female cymule with

3 flowers, sepals 7-11, unequal and slender-pinnatifid

with 4-6 slender lobes/side; ovary densely hispid, stylar

column 5-6 mm long, stigma 0.6-1 mm wide. Fruits 5-

6 mm long, 8-10 mm wide, with 3 rounded lobes, mi-

nutely puberulent, subtended by sharp-hispid pinnatifid

sepals 7-1 1 mm long, 0.6-2 mm wide, lobes 0.5-2 mm

long, stinging hairs to 1 mm long, columella 2.8-4.2 mm

long, 3.7-4.2 wide at apex; seeds 2.8-4.2 mm long, glo-

bose, dark to pale brown, smooth, usually mottled.

Plants of evergreen forest formations of the Pa-

cific slope, 400-1 100 m elevation (0-1 500 in Gua-

temala). Fruiting in November-March. Collected

only on the Cordilleras de Guanacaste and Tilaran

and near San Ramon in Costa Rica (but see below).

The species ranges from Mexico to Peru.

Dalechampia cissifolia is recognized by its pal-

mately three-foliolate leaves (rarely simple and

ovate), greenish involucral bracts often with three

distal lobes, and the "involucre" of 7-1 1 stiff nar-

row sepals with short narrow lateral lobes and

stinging hairs subtending the fruits. It is possible

106

FIELDIANA: BOTANY

that D. heteromorpha will be reinterpreted as an

unusual form of this species.

Dalechampia dioscoreifolia Poeppig in Poeppig &

Endl., Nov. gen. sp. pi. 3: 20. 1841. Figure 5.

Climbing vines, leafy stems 1 .2-4 mm thick, minutely

puberulent with thin mostly retrorse hairs 0.1-0.3 mm

long, older stems becoming dark brown with rounded

lenticels ca. 0.4 mm wide; stipules 3-7 mm long, 1.1-2

mm wide at the base, lanceolate to narrowly triangular,

venation parallel, reflexed, persisting. Leaves simple,

petioles 1 .6-10.3 cm long, 0.7-1 .4 mm thick, puberulent,

with 2 linear stipels at base of blade near petiole attach-

ment, 0.7-4.3 mm long, 0.2-0.5 mm wide; leaf blades

6-15 cm long, 4-13 cm wide, ovate to ovate-triangular,

apex short-acuminate to acuminate, tip 3-10 mm long,

margin entire or minutely (0.3 mm) denticulate, base

cordate to subcordate-truncate, drying chartaceous, up-

per surfaces minutely puberulent on the major veins,

lower surface with minute puberulence on all the veins,

venation palmate with 3 major ascending veins and 2

lesser laterals, 2° veins 1-3/side of midvein. Inflores-

cences on short (0.5-8 mm) axillary branches, peduncles

3-18 mm long, 0.6-1 mm thick, minutely puberulent,

involucral stipules 4—10 mm long, ovate-triangular; in-

volucral bracts 15-50 mm long, 18-50 mm wide, ovate

to ovate-triangular, base cordate, often with a thick (1.3-

2 mm) petiole 6-1 1 mm long, pinkish or white with

darker red or purple venation, margin with prominent

(2-6 mm) teeth, with 5-7 major veins; resin dark purple.

Male cy mules on peduncles to 1.5 mm long, involucel

of 4 free broadly imbricate concave bracteoles, 6 flowers

8-9, pedicels 3-6 mm long, puberulent distally, calyx

lobes 4, puberulent on exterior, staminal column 2.5-

3.5 mm long, glabrous, anthers 20-30. Female cymules

with abaxial bracteoles ca. 5 mm long, concave, glabrous

with ciliate margin; 9 flowers with 5-1 1 narrow pinna tifid

sepals with slender lobes, pubescent; ovary densely his-

pidulous, styles 3-5.5 mm long, stigmas 1.5-4 mm wide,

rounded, flat and peltate. Fruits 8-10 mm long, 11-16

mm wide, deeply 3-lobed, sparsely pubescent with hairs

0.1-0.4 mm long, thick-walled (to 2 mm), subtended by

sepals 10-16 mm long, central rachis to 1.3 mm wide,

lateral lobes 4-12 mm long, 0.3 mm wide, hairs ca. 0.4

mm long, columella 4.5-5 mm long, 4-5 mm wide at

apex, T-shaped; seeds 4.5-5.8 mm long, 4.5-6 mm wide,

3.3-4.5 mm thick, lenticular-triangular in cross-section,

with a distal longitudinal peripheral ridge and 2 parallel

longitudinal adaxial ridges, slightly rugose.

Plants of evergreen rain forest formations of the

Caribbean and southern Pacific slopes at 10-1 100

m elevation. Flowering and fruiting throughout

the year. The species ranges from southeastern

Nicaragua to Peru.

Dalechampia dioscoreifolia is recognized by its

simple unlobed cordate leaves, bright pink invo-

lucral bracts with dark reddish veins against a pal-

er background, peltate stigmas, fruits subtended

by narrow sepals with long lateral lobes and sting-

ing hairs, and unusual seeds with longitudinal ridg-

es. The involucral bracts often have prominent

petioles.

Dalechampia heteromorpha Pax & K. Hoffm.,

Pflanzenreich IV, 147, XII: 26. 1919. D. gua-

temalensis Gandoger, Bull. Soc. Bot. Fr. 66:

286. 1920. D. molliuscula Blake, Contr. U.S.

Natl. Herb. 24: 12. 1922. Figure 5.

Clambering vines, leafy stems 0.6-1.8 mm thick, with

thin retrorse whitish hairs 0.1-0.5 mm long; stipules 2-

6 mm long, 0.6-0.8 mm wide at base, narrowly lanceo-

late-linear, sparsely puberulent, venation obscure, per-

sisting or deciduous. Leaves varying on the same stem,

simple and ovate to 3-foliolate, petioles 1.2-1 1 cm long,

0.5-1.6 mm thick, sparsely pubescent, stipels often pres-

ent, 1-4 mm long, ca. 0.4 mm wide, petiolules 0-3 mm

long; leaf blades of simple leaves 3-14 cm long, 2-8 cm

wide, narrowly ovate-triangular with cordate or subcor-

datebase, central blade of 3-foliolate leaves 3-1 1 x 1.4-

3.2 cm, narrowly elliptic or narrowly elliptic-oblong to

oblanceolate, apices acuminate, margins denticulate to

rounded -crenate or subentire, teeth 3-6/cm, base of lat-

eral leaflets asymmetric and rounded on the outer side,

drying chartaceous, with thin straight hairs 0.2-1.1 mm

long (shorter beneath), simple leaves with palmate ve-

nation and 3 (5) major veins and 2° veins 2-3/side, lateral

leaflets with 2 major veins, 3° veins subparallel. Inflo-

rescences on axillary stems 1-5 cm long, peduncles 0.5-

0.9 mm thick, pubescent, involucral stipules 2-3 mm

long, 0.4-1 mm wide at base, puberulent; involucral bracts

1-2 cm long at anthesis and green, becoming 1 6-27 long

and 16-30 mm wide in fruit, ovate to broadly ovate,

margin undivided with small (0.2 mm) glandular teeth

or deeply 3-lobed, sparsely pubescent. Male flowers with

connate involucellar bracteoles; stamens 20-30 and

crowded. Female flowers with ca. 1 0 narrow sepals with

narrow pinnatifid lobes, with stiff yellowish hairs ca. 1

mm long; ovary pubescent, stylar column 3-4 mm long,

slightly expanded at apex. Fruits ca. 6 mm long, 7-10

mm wide, with 3 rounded lobes, minutely (0.1-0.2 mm)

puberulent, subtended by the pinnatifid sepals 7-10 mm

long with narrow (0.5-1 mm) central axis with 3-7 nar-

row lobes 1-1.4 mm long and stiff sharp hairs 0.8-1.5

mm long; seeds 3.4-4.3 mm diam., subglobose, mottled

brown to dark brown, smooth.

Plants often found in secondary growth in ev-

ergreen forest areas, 0-1 100 m elevation. Flow-

ering throughout the year. First collected in Costa

Rica (Brenes 14414 the type), the species ranges

from Veracruz, Mexico, to southernmost Puntare-

nas (but see below).

Dalechampia heteromorpha is recognized by

having both ovate-triangular leaves and three-fo-

liolate leaves (often on the same short length of

stem) and the linear-oblong 9 sepals with narrow

pinnatifid lateral lobes and sharp hairs. The lateral

BURGER & HUFT: FLORA COSTARICENSIS