1 !»<••_> | 



LEAFY HEPATICAE OP LATIN AMERICA — PART I 



17 



Key to the Genera 



1, Leaves and Underleaves undivided or only emarginate. 



2. Stems erect; leaves and underleaves similar in form and length. 

 3. Plants green or brownish. 



4. Leaves large, rounded; antheridia borne <m terminal discs surrounded by 



bracts and bracteoles. Calobryum. 

 A. Leaves acute; antheridia axillary on short ventral sexual branches. 



Micropterygium. 



::. Plants dark brown; leaves ovate to ovate-lanceolate; antheridia axillary; arche- 

 gonia few at the tip of the stem; leaves and underleaves several layers of 

 cells thick. Pachyglossa. 



2. Stems distinctly doisiventral, prostrate to ascending. 



3. Leafy stems irregularly pinnately branched; leaves often winged-keeled above. 



Micropterygium. 



3. Peaty stems appearing to be dichotomously branched; underleaves smaller than 

 and different from the leaves (subentire species of Bazzania and Acromasti- 

 gum). 



4. Leafy branches with seven longitudinal rows of cortical cells. Acromastigum. 

 4. Leafy branches with more than seven rows of cortical cells. Bazzania. 



1. Leaves variously divided. 



2. Leaves almost wholly divided into filiform segments, or appearing as masses of 

 intricately interwoven cilia; lamina (when present) obscured by the mass of cilia. 

 3. Leaves 2-, 3-, or 4-parted to the base, the segments unbranched, capillaceous ; 



leaves transversely inserted. Telaranea. 

 3. Leaves with a lamina, the segments and margins ciliate; leaves obliquely in- 

 serted and ineubous or succubous, or transversely inserted. 

 4. Leaves ineubous, divided to the middle; cilia in opposite pairs on the seg- 

 ments, the cells short. Lepidozia. 

 4. Leaves succubous or transversely inserted. 



5. Stems sparingly and irregularly branched, brownish-green; perianth long, 

 with three rounded keels above, the surface without paraphyllia, the mouth 

 not contracted. Temnoma. 

 5. Stems distantly pinnate to closely and regularly bi- or tripinnate, light 

 green, never pigmented with brown; perianth (if present), densely covered 

 with paraphyllia ; in some species a partial or complete coelocaule de- 

 veloped. Trichocolea. 

 2. Leaves variously divided, at least a part of the lamina conspicuous. 

 3. Leaves bifid; plants small to large, pigmented with brown. 

 4. Plants small, light greenish-brown. 



5. Leaves two or more times as long as the underleaves; underleaves spinose- 



dentate. Triandrophyllum. 

 5. Leaves and underleaves alike or nearly so. 



6. Branches frequent, both lateral and ventral ; leaves transversely inserted 

 (some 3-toothed) ; cortical cells of the stem in 12 longitudinal 

 rows. Par acromastigum. 



6. Branches rarely produced, ventral (rarely lateral) ; leaves and under- 

 leaves obliquely inserted, ineubous ; cortical cells of the stem in many 

 rows, smaller. 



7. Line of leaf insertion hook-form or recurved at the dorsal end ; sporo- 

 phyte in a perianth ; antheridia in the axils of both the male bracts 

 and bracteoles Triandrophyllum. 

 7. Line of leaf insertion not hook-form above, sporophyte enclosed in an 



erect perigynium; antheridia only in the axils of the male bracts. Isotachis. 

 4. Plants larger, often tending to be erect or pendent. 



5. Underleaves as large as and like the leaves, if smaller of a similar general 

 pattern. 



6. Leaves long, rectangular to ovate-truncate, deeply bifid; segments long, 

 lanceolate; cells thick-walled, of the margins more or less quadrate, of 

 the inner part elongate forming a vitta ; line of leaf insertion transverse 

 or nearly so. Hcrberta. 



