Evans : HEpATICAE OF PuERTO RIco 505 
Brownish-green, growing in thin, irregular patches: stems 
prostrate, 0.06 mm. in diameter, irregularly pinnate, the branches 
widely spreading, those bearing propagula microphyllous : leaves 
distant to contiguous, the lobe obliquely spreading, plane or with 
slightly revolute margins near the apex, ovate to ovate-lanceolate, 
distinctly narrowed toward the base, 0.6 mm. long, 0.25 mm. 
wide, attached by an almost longitudinal line of insertion, margin 
denticulate except in basal region, the teeth usually projections of 
single cells, rarely composed of from 1 to 3 cells, antical margin 
somewhat more convex than postical, apex acute, tipped with a 
single cell or with 2 superimposed cells ; lobule oblong, 0.2 mm. 
long, 0.14 mm. wide, inflated toward base and along keel, plane 
and appressed to lobe in outer part, keel slightly arched, forming 
an almost continuous line with postical margin of lobe, free mar- 
gin involute toward base, passing beyond apex by a lunulate 
sinus to end of keel, apex formed by a single, strongly curved 
cell separated by a slight indentation from the inner part of the 
free margin; cells of lobe plane or nearly so, averaging 14 p at 
the edge, 23 x 13 w in the middle and at the base, thin-walled 
throughout or more rarely with indistinct and more or less con- 
fluent local thickenings ; ocelli indistinct, but present in well- 
developed leaves, varying in number from I to 6, usually 4, 
arranged in an interrupted longitudinal row, those near the base of 
lobe measuring 35 x 23 yz, those in outer part averaging 23 x 16 p: 
underleaves distant, basal portion trapezoidal in outline, often 
abruptly contracted at base, 0.05 mm. long, 0.09 mm. wide, 
Marginal cells 6, the second cells more or less bulging, divisions 
obliquely spreading, 3 or 4 cells long, 1 or 2 cells wide at base, 
the cells very slightly bulging, cluster of rhizoids sometimes 
replaced by a sucker-like disc: inflorescence dioicous: ? inflo- 
rescence borne on a very short branch, innovating on one side with 
a short, simple and sterile innovation ; underleaf at base of branch 
usually with a sucker-like disc ; bracts erect-spreading, complicate, 
Shortly and unequally bifid, the lobe ovate, 0.45 mm. long, 0.2 
mm. wide, acute, sharply and irregularly denticulate above the 
middle : lobule oblong, 0.35 mm. long, 0.1 mm. wide, truncate to 
acute at the apex, denticulate ; bracteole connate on one side, 
oblong-obovate, 0.4 mm. long, 0.17 mm. wide, bifid about one 
third with acute divisions and sinus, margin irregularly denticulate 
Or Crenulate in upper part ; perianth obpyramidal, shortly rostellate, 
9:55 mm, long, 0.45 mm. wide at apex, 5-keeled, the keels 
dilated and truncate in upper part, smooth or nearly so: é inflo- 
“scence terminal on a short branch ; bracts in 5 to 12 pairs, imbri- 
cated, strongly inflated, shortly bifid, the lobe obtuse, the lobule 
rounded, Margins subentire, keel strongly arched, denticulate in 
