1962J 



LEAFY HEPATICAE OP LATIN AMERICA — PART [ 



77 



11. Isotachis fragilis Stephani, Sv. Vet.-akad. Handl. 46'-': 67. f. So, b, c. 1911. 



Plants of small to medium size, dark brown to brownish-green, ascending to 

 erect, in tufts or cushions; stems 2--3 em long, with leaves to 1.7 mm wide, often 

 branched, the branches near the base of the stem; steins in transverse section 

 12-14 cells in diameter, the cortical band of two layers of cells with very thick- 

 walls, the cells of the medulla larger, with thinner walls. Rhizoids not seen. 

 Leaves imbricate, widely spreading, canaliculate, broadly ovate-truncate to 

 orbicular, bifid to one-fourth of their length; segments erect, obtuse, the sinus 

 broad, rounded; leaf margins entire or with an occasional tooth at about the 

 middle; cells of the median portion of the lamina averaging 47 X 16 /*, the walls 

 uniformly thin, trigones inconspicuous or absent, the cells of the margin and 

 the segments smaller, the cuticle smooth. Underleaves nearly as large as the 

 leaves, similar, orbicular, with one or two lateral teeth. Male and female inflo- 

 rescences and sporophytes not seen. Fig. 11, a-d. 



Habitat : Not given. 



PATAGONIA— TIERRA DEL FUEGO: s.l., Skottsberg 886, (type G). [Stephani 

 (1911) has listed two localities, Isla Atalaya and Tal n. von Lago Fagnano, but does not 

 cite collection numbers with these localities; the packet containing the type material does 

 not give locality.] 



12. Isotachis splendens Stephani, Hedwigia 34: 49. 1895. 



Plants large, bright red to magenta, prostrate to ascending, in mats or cush- 

 ions; stems -V10 cm long, with leaves 3-4 mm wide, sparingly branched; stem 

 in transverse section 12-15 cells in diameter, the cortex of one or two layers of 

 smaller cells with slightly thicker walls than the large cells of the medulla. 

 Rhizoids not seen. Leaves flaccid, erect-spreading, canaliculate, bifid to two- 

 thirds or four-fifths; segments long, narrowly ovate-truncate to ligulate, diver- 

 gent, the sinus very broad; leaf margins entire with one or two obscure or poorly 

 defined teeth ; cells of the median portion of the leaf averaging 108 X 35 p., the 

 walls thin, the trigones very small or absent, the cells of the marginal one or 

 two rows long, narrow, forming a conspicuous border, the cuticle smooth. Un- 

 derleaves as long as the leaves, ligulate to narrowly ovate, bidentate or refuse. 

 Male and female inflorescences and sporophyte not seen. Fig. 12, a-f. 



Habitat : Not given. 



PATAGONIA— TIERRA DEL FUEGO: Straits of Magellan, Tuesday Bay, Cunning- 

 ham 159, (type G, isotype FH) ; Desolation I., Itusen (G). 



Fig. 13. Isotachis obtusiloba. 13 a. Stem, ventral view, X 9- 13 b. Leaf, X 18. 13 c. 

 Cells from the median portion of a leaf, X 165. 13 d. Underleaf, X 18. 



Fig. 14. I. lacustris. 14 a. Stem, ventral view, X 9- 14 b. Leaf, X 18. 14 e. Cells 

 from the median portion of a leaf, X 165. 14 d. Underleaf, X 18. 



Fig. 15. 7. obtusa. 15 a. Stem, ventral view, X 9. 15 b. Leaf, X 18. 15 c. Cells 

 from the median portion of a leaf, X 165. 15 d. Underleaf, X 18. 



Fig. 16. I. spegazziniana. 16 a. Stem, ventral view, X 9. 16 b. Leaf, X 18. 16 c. 

 Cells from the median portion of a leaf, X 165. 16 d. Underleaf, X 18. 16 e. Portion of 

 a transverse section of a stem, X 165. 16 f. Female bract of the outer series, X 25. 16 g. 

 Female bract of the innermost series, X 25. 16 h. Section through a perigynium, X 25; X, 

 sporophyte; A, foot of the sporophyte; H, hyaline portion, the perianth; T, the thick wall. 

 16 j. Young sporophyte, X 25; A, foot with a covering tissue; S, seta; C, capsule. 



Drawn from Hatcher, 1960, except 16 f-j. 



