UNIVERSITY OF ILLINOIS LIBRARY AT URBANA CHAMPAIGN Ou ^ ^BIOLOGY JUL11198* FIELDIANA Botany Published by Field Museum of Natural History Volume 38, No. 7 August 20, 1977 Austral Hepaticae IX Anastrophyllum tristanianum, A New Species from Tristan da Cunha JOHN J. ENGEL' DONALD RICHARDS ASSISTANT CURATOR OF BRYOLOGY FIELD MUSEUM OF NATURAL HISTORY Anastrophyllum tristanianum Engel, n. sp. Simile Anastrophyllo crebrifolio (Hook. f. & Tayl.) Steph., sed differt 1) foliorum margine integro; 2) cellulis foliorum medianis trigonis magnis et parietibus tenuibus separatis institutis; 3) sto- lonibus praesentibus; 4) ramifications typi Frullaniae nulla. Holotype: Tristan da Cunha, above Burntwood, 650 m., 10 Janu- ary 1938, Christophersen & Mejland 889 (0! ). Plants soft, rather spongy, somewhat brittle, red brown to yellow brown, the axis tips usually deep red to magenta; plants in nearly pure, compact mats or loosely intermixed with other bryophytes; axes suberect, rather robust, 1.3-1.8 mm. wide, the axes commonly increasing in size toward the apex or with swollen, intercalary regions. Branching rather frequent, of lateral-intercalary type, terminal branching absent; lateral-intercalary stolons rather common, the stolons narrow, wirelike, leafless, with rhizoids. Stems rather rigid, red brown, 1 70-2 15 p. thick, 220-320/1 wide, of 15-16 cells thick, somewhat dorsiventrally flattened; cortex in 3-4 rows of distinctly thick-walled, pigmented cells, but with outermost row with radial walls only moderately thick- 'I wish to extend grateful thanks to Dr. Anna-Elise Torkelsen, Botanical Museum, Oslo, Norway, for the loan of specimens, to Mr. William Petersen for assistance with the plates, and to Dr. Rolf Singer for assistance with the Latin diagnosis. US ISSN 0015-0746 Library of Congress Catalog Card Number: 77-839-49 '" Llbrary of the Publication 1267 71 APR 05 1978 '978 '*» BIOLOSV 101 BURSIU HAU 72 FIELDIANA: BOTANY, VOLUME 38 FIG. 1. Anastrophyllum tristanianum Engel. 1, portion of main axis, dorsal view, note ensheathing leaf bases; 2-5, leaves (flattened; vl = ventral lobe); 6-8, dorsal lobe(= dl) apices of leaves; 9-11, ventral lobe (= vl) apices of leaves; 12, median leaf cells. Numbers 1-3, 7-10, 12 from holotype material; 4 from Christophersen & Mej- Iand235\ 5, 6, 11 from Christophersen & Mejland232. ened and exposed wall thin or slightly thickened; medullary cells thin-walled, the corners thickened similarly to small trigones. Rhizoids not seen on leafy axes. Leaves 0.9-1.2 mm. from segment Apices to leaf insertion, 1.3-1.4 mm. wide, dorsal half ±. transversely inserted, the base dilated and extending across and often some- what beyond stem, not decurrent, the ventral half obliquely inserted, not decurrent; leaves strongly spreading, imbricate (closely so from ventral aspect), somewhat dorsally secund with axes thus appearing strongly convex in ventral aspect, deeply concave, the ventral half of leaf deeply concave-subcupulate (in ventral view leaves with an elongate, distinct, broad, convex bulge); leaves asymmetrically broadly ovate, the margins broadly rounded (the ventral margin semicircular in outline, much more round than the dorsal margin), entire; leaves 0.25-0.45 bifid; lobes entire, acutely triangular, the apices rounded or tapering to a rather sharp tip, often hyaline; dorsal lobe slightly incurved (and then entire leaf deeply concave), erect or 8& ENGEL: AUSTRAL HEPATICAE IX 73 (? FlG. 2. Anastrophyllum tristanianum Engel. 1, stem, cross-section; 2, 3, portion of axis, dorsal and ventral views respectively (note leaf insertion); 4, male bracts show- ing antheridia (= a) and paraphyses (= p); 5, large paraphysis from axil of male bract shown in 4; 6, portion of main axis with three stolons; 7, portion of axis with perianth, lateral-ventral view. All from holotype material. broadly recurved, 1.1-1.3X wider than long, 0.5-0.75X area of ventral lobe; ventral lobe somewhat incurved, 1.0-1.9X wider than long; sinus rounded or truncate. Un- derleaves absent. Gemmae absent. Median leaf cells with large, bulging, often knotlike trigones which are rarely confluent, the intervening walls thin, the cells 12-24/x wide, 18-26yu, long; subapical lobe cells 17-24 (-26) /i wide, 16-26/1 long; basal cells moderately elongated, the trigones less pronounced. Cuticle faintly striate. Dioecious; androecia becoming intercalary on main axes or long branches; bracts in 3-5 pairs, of similar size to leaves, the bracts strongly saccate at dorsal base, sim- ilar to leaves except dorsal margin usually with a tooth or lacinium at the base; antheridia (1-) 2-3 per bract; paraphyses variable, rudimentary or lobelike and 74 FIELDIANA: BOTANY, VOLUME 38 acute, to ca. 0.5 leaf length, issuing from median, dorsal portion of stem or from bract axil. Gynoecia on main axes, without subfloral innovations; bracts rather closely imbri- cate, opposing pairs laterally strongly overlapping one another, those of innermost series erect, sheathing base of perianth, concave, especially so at the immediate base where sharply, abruptly concave, the bracts bifid to ca. 0.35-0.5; bract lobes entire, erect, deeply concave, acutely or obtusely triangular, the apices sharp, often apicu- late, the sinus sometimes gibbose; dorsal margin of bract with 1-2 sharp teeth, the ventral margin of bract with 1-2 small or large teeth; bract of innermost series some- times vestigial and considerably smaller than that of next outermost series. Peri- anth ca. 2.5-4 mm. long, 1.0-1.1 mm. wide, 0.55-0.6 emergent, subcylindrical, 5 plicate in distal 0.5-0.75, the plicae pronounced, rounded, with 3-4 sulci descending below level of bracts; perianth contracted at the hyaline mouth, the mouth irregu- larly dentate by unicellular very thick-walled teeth which extend for varying lengths. Anastrophyllum tristanianum is rather closely related to A. creb- rifolium ( Hook, f . & Tayl. ) Steph. of southern South America and north in the Andes to Ecuador, from which it differs in the following features: 1) leaves with dorsal margins entire throughout; 2) medi- an leaf cells with large trigones separated by thin walls, the trigones only rarely confluent; 3) stolons present; and 4) Frullania-type branching absent. Anastrophyllum crebri folium, on the other hand, has 1) leaves with dorsal margins 1(2-3) laciniate-lobate or occasion- ally dentate at the base; 2) median leaf cells with large, confluent trigones, or if not confluent, then with the intervening walls thick- ened; 3) stolons absent; and 4) Frullania-type branching occasion- ally present. Ecology-Phytogeography. —Endemic to Tristan da Cunha where on ground or tree ferns, 200-650 m. Specimens seen. —Tristan da Cunha, above Burntwood, 650 m., 10 January 1938, Christophersen & Mejland 889 (Holotype)(0); above settlement, 200 m., 21 December 1937, Christophersen & Mejland 232, 235(0). UNIVERSITY OF ILLINOIS-URBANA