UNIVERSITY or

JUL 2 4 1984

Hie Library of the

FIELDIANA JAN is 1979

^VlCllljf at Uibana-Champaifzn

Published by Field Museum of Natural History

•

Volume 36, No. 7 April 10, 1974

Notes on the Genus Hygrolembidium (Hepaticae)1

JOHN J. ENGEL

DONALD RICHARDS ASSISTANT CURATOR OF BRYOLOGY

KIELD Mi SHI M 01- NATIRAI. HISTORY

Study of several large collections of Hepaticae from southern

South America has revealed perianth- and sporophyte-bearing

plants, both of which are heretofore unknown for the species.

With these structures at hand, the relationships and taxonomic

position of this taxon may be assessed with greater certainty.

Hygrolembidium isophyllum Schust. Nova Hedwigia 15: 467.

pi. 56. 1968.

Holotype.— Argentina, Tierra del Fuego, Paso Garibaldi, near

Lago Escondido, Schuster 583 19e (RMS!).

Schuster (1968) described Hygrolembidium isophyllum from

Tierra del Fuego, but at the same time reflected his uncertainty

regarding the systematic position of this taxon when he stated (p.

467), "Allied to Isolembidium and possibly also to Hygrolembid-

ium is another undescribed taxon which serves, in some ways, to

connect Hygrolembidium and Isolembidium^ yet differs from both

taxa." Schuster (loc. cit.) emphasized the uniqueness of the

species when he described for it a monotypic subgenus (subg.

Hygrobiellopsis). Through the study of several collections of H.

isophyllum, especially sporophyte-bearing material, the relation-

ships of the taxon may be assessed with greater certainty. In

'Grateful acknowledgement is made to the National Science Foundation

(grant GA-1192 to Dr. Henry A. Imshaug, Michigan State University) for

support of field work. I also thank Drs. T. Ahti and H. Roivainen (H) and

P.B. Whitford (UW-M) for facilitating specimen loans.

Library of Congress Catalog Card Number: 74-75773

101 oUKKILL

US ISSN 001 5-0746

Publication 1181 61

1 9 1979

62 FIELDIANA: BOTANY, VOLUME 36

addition, the study of these collections has provided useful

information regarding the ecology and phytogeography of the

species.

Schuster (1968) stated the leaves of //. isophyllum were

unistratose, and utilized this character in differentiating it from

Isolembidium and the remainder of Hygrolembidium taxa. I have

found the leaves of H. isophyllum to be 2-3 stratose in the median

basal portion, with marginal areas unistratose. The leaves, how-

ever, may have polystratose regions scattered among areas of a

single cell layer. The possession of at least locally polystratose

leaves aids in establishing the rather close relationship of this

taxon to both Hygrolembidium and Isolembidium.

The margins and apices of leaf and underleaf of Hygrolem-

bidium isophyllum have several (8-20) slime papillae. The papillae

are usually mounted directly on the margin but may be on the tip

of a 1 -several-celled tooth. There is no mention of slime papillae or

teeth in the original description or indication of their presence in

the figures of the taxon in Schuster (1968). I have, through the

kindness of Dr. R.M. Schuster, studied holotype material of

Hygrolembidium isophyllum and confirmed the presence of these

structures in the original material. Neither Isolembidium nor the

remainder of Hygrolembidium taxa possess slime papillae, and the

presence of this character in H. isophyllum aids in the distinction

of subgenus Hygrobiellopsis. The perianth mouth, bract, and

bracteole margins and apices are likewise ornamented with slime

papillae. The perianth mouth and bracts of Hygrolembidium

andinum Herz. may have slime papillae, judging from the general

appearance of the structures figured, but not described, in Herzog

(1954, fig. 8e, h), but the leaves are entire and without slime

papillae. I have not seen the type material of this taxon.

Hygrolembidium isophyllum was described on the basis of

completely sterile material. Study of fertile material of this species

has shown the perianths of H. isophyllum and those of the

remainder of Hygrolembidium taxa compare somewhat in general

shape, i.e., trigonous, fusiform to elongate-ovate, and contracted

toward the mouth. Hygrolembidium isophyllum however, is

pluriplicate in the upper one-half.

Hygrolembidium isophyllum, like the other members of the

genus, possesses a Lepidozia-type seta anatomy [8-16 (-20) rows

of large epidermal cells surrounding an indefinite number of

interior rows of cells] . While Hygrolembidium isodictyon has 17

rows of epidermal cells and H. stereophyllum 16 rows (fide

nr

FIG. 1. Hygrolembidium isophyllum Schust. A, portion of plant with

perianth, X 20; B, capsule with portion of seta, X 20; C-E, perianth, cross

sections at ca. one-fourth distance from apex, middle, and base respectively,

X 37; F, perianth mouth showing 5 slime papillae, x 175; G, elater, X 450; H,

spore x 450; I, innermost bract, cross-section through base, X 90; J, inner

cells of capsule wall, x 450; K, capsule wall, cross-section, x 450; L, bract of

innermost series, lateral view, X 20; M, bract apex of innermost series showing

a slime papilla, X 450; N, seta, cross-section, x 90; O, outer cells of capsule

wall, X 450. Figure A from Hatcher 15-13, Chile, Prov. Magallanes, Puerto

Natales. Figure B-0 from Engel 1982, Chile, Prov. Magallanes, Brunswick

Peninsula, 8 km. W of Punta Arenas.

63

64 FIELDIANA: BOTANY, VOLUME 36

Herzog, 1951, figs. 7, 9, respectively), H. isophyllum has 18-20

rows. The capsule wall anatomy of H. isophyllum differs some-

what from H. stereophyllum, to my knowledge the only other

member of the genus known with sporophytes. Hygrolembidium

isophyllum has 4-6 stratose capsule walls while H. stereophyllum

has bistratose walls (fide Herzog, 1951).

Hygrolembidium isophyllum shares several critical features with

Hygrolembidium and Isolembidium and indeed may be said to

"connect" the two taxa. Hygrolembidium isophyllum has the

isophylly and polystratose, deeply concave leaves of Isolembidium

but differs in a) stem cells thin-walled throughout, without a

hyaloderm but with a cortex of small cells, b) leaf margins with

slime papillae, c) cells thin to uniformly thickened, and with

trigones absent, and d) the exclusively intercalary branching. Like

subgenus Hygrolembidium, subgenus Hygrobiellopsis has poly-

stratose leaves, exclusively intercalary branching, and a Lepidozia-

type seta anatomy, but the latter differs in a) the small-celled

cortex with an absence of a hyaloderm, b) the perfect isophylly, c)

the presence of slime papillae on the leaves, d) the pluriplicate

(upper one-half) perianth, and e) the 4-6 stratose capsule walls.

In working with collections from southern South America, I

have previously recognized Hygrobiellopsis as a distinct genus. I

now believe, however, the differences outlined above are not

sufficient generic criteria, but rather serve to emphasize that a

distinct subgenus is at hand.

On the basis of fertile material examined, I am providing below

a detailed description of the gynoceium and sporophyte of

Hygrolembidium isophyllum.

Plants dioicous; androecia not seen. Gynoecia on short intercalary

branches; bracts and bracteoles in 3 series, bracts of innermost series 2 cell

layers thick in basal region, marginal 2-6 rows unistratose, deeply concave to

subnaviculariform, ovate, margins and especially apices with slime papillae;

bracteoles concave, not nearly as concave as bracts, broadly ovate, apices

broadly rounded, margins and apices with slime papillae. Perianth with basal

portion 2 cell layers thick, 3 layers thick only very locally, median portion

mostly unistratose, but with scattered regions of 2 cell layers, upper one-third

unistratose throughout, one-fourth to one-half emergent, fusiform to wide

ovate, obscurely to distinctly trigonous in lower one-half, keels, when

present, rounded, not sharp, upper one-half pluriplicate, perianth

contracted toward the mouth, the mouth with several small lobes, with slime

papillae, subapical perianth cells irregularly rectangular, 52-77 n long, 20-26 M

wide.

ENGEL: NOTES ON HYGROLEMBIDIUM

65

FIG. 2. Hygrolcmbidium isopliyllum Schust. Scanning electron photo-

graph of spore, x 5,700.

Seta of the Lepidozia type, 10 cells in diameter, with 18-20 epidermal cells

(52-62 n in diameter) in very regular longitudinal rows surrounding an inner

core of an indefinite number of cells (26-) 33-48 n in diameter, corners

slightly thickened. Capsule broadly ovate, 1.1 mm. long, 0.9 mm. wide,

capsule wall 52-59 ^ thick, of 4-6 layers, outer row of large cells and the

inner 3-5 rows of smaller cells of approximately equal size, outer row of cells

regularly to irregularly rectangular or subsquarrose in shape, 39-60 /u long,

13-26 M wide, 18-26 n thick, outer layer with radial walls with small to quite

large red-brown nodular thickenings which have been interconnected by

sheetlike thickenings, the thickenings strictly I-shaped or feebly extending

onto outer tangential wall, radial walls occasionally thin walled and without

thickenings; intermediate cell layers with or without radial thickenings,

thickenings occasionally extending slightly onto outer tangential walls; inner

66 FIELDIANA: BOTANY, VOLUME 36

layer of cells irregularly rectangular in shape, 55-79 n long, 10-22 n wide,

7-12 M thick, inner wall with usually incomplete semiannular bands or with

nodular extensions of various lengths from sparingly developed swellings on

the radial walls, rarely with complete semiannular band, swellings often

without bands or extensions, radial walls occasionally without thickenings.

Spores 17-21 /u, red brown, globose or broadly ovate in shape, covered with

numerous vermiculate, short to long, closely arranged, irregular, occasionally

branched ridges. Elaters usually long and slender, 126-169 n long, 8-12 M

wide, occasionally shorter and stouter and to 17 ju wide, gradually tapering at

both ends, usually bispiral throughout, occasionally 3 or 4 spiraled in median

portion and bispiraled only at tips, spirals yellow brown.

Ecology -Phytogeography— In the Falkland Islands this species

seems to be restricted to sheltered cliffs above 610 m., where it

grows on soil under rock overhangs or on Azorella cushions. In the

Brunswick Peninsula (Chile, Strait of Magellan) I found the species

only in the relatively dry eastern end (8 km. west of Punta Arenas,

305-610 m.), and here it grew on soil among cushion plants.

Raymond E. Hatcher made several collections of the taxon in bogs

between Punta Arenas and Puerto Natales, ca. 100 km. north of

the Strait of Magellan, a locality which is on the eastern side of the

Andes and thus relatively dry. The species is otherwise known

only from between 420 and 790 m. on Isla Grande de Tierra del

Fuego. On the mainland this taxon seems to be restricted to

deciduous Nothofagus forests of magellanian South America.

Specimens seen. -FALKLAND ISLANDS. EAST FALKLANDS.

MT. USBORNE REGION: ridge between Mt. Usbornes 1 & 2, 685

m., Engel 2522, 2556 (MSC). WEST FALKLANDS. PORT HOW-

ARD: pass southwest of Mt. Maria summit, c. 610 m., Engel 3102

(MSC); MT. ADAM: east side of summit ridge, 670-700 m., Engel

3008 (MSC). ARGENTINA. TIERRA DEL FUEGO: east side of

Paso Garibaldi, Sierra Lucas Bridges (54° 42' S., 67° 45' W), 790

m., Crow 1711 (MSC); Paso Garibaldi, Cerro Gabriela (54° 39' S.,

67° 55' W.), 580 m., Roiuainen 685~c. per. (H); Paso Garibaldi, at

54° 40' S., 67° 55' W., 420 m., Roiuainen 685 b (H); west side of

Paso Garibaldi, Sierra Alvear, 460 m., Crow 1443 (MSC); north

slope of mountain to east of Monte Olivia, Sierra de Sorondo, 670

m., Crow 1828 (MSC). CHILE. MAGALLANES: ridge above

refugio (Club Andino), 8 km. west of Punta Arenas, 305-610 m.,

Engel 1982— c. per. + sporo. (MSC); near road between Punta

Arenas and Puerto Natales, ca. 100 km. north of the Strait of

Magellan, Ha tcher 14-6, 15-13-c. per. ,17-15 (UW-M).

ENGEL: NOTES ON HYGROLEMBIDIUM 67

REFERENCES

HERZOG, T.

1951. Revision der Lebermoosgattung Lembidium Mitt. Ark. Bot., II., 1,

pp. 471-503, figs. 1-13.

1954. Zur Bryophytenflora Chiles. Revue Bryol. Lichen., 23, pp. 27-99,

figs. 1-24.

SCHUSTER, R.M.

1968. Studies on Hepaticae, XXIX-XLIV. A miscellany of new taxa and

new range extensions. Nova Hedwigia, 15, pp. 437-529, pi. 49-67.

UNIVERSITY OF ILLINOIS-URBANA