Evans: HEPpaTICAE OF PUERTO Rico 551 
plements, in several important respects, the original description, 
which was drawn from sterile material. A. uncinata is about the 
same size as H7. swbacuta and resembles it closely at first glance. 
It is remarkable for the long and slender apices of its lobes, which 
stand out from the axis at an angle of go0° or more in explanate 
leaves. This character will at once distinguish the species from 
(1, subacuta and the denticulate or crenulate leaf-margins will also 
be of assistance. Lobules,:leaf-cells, ocelli and underleaves are 
strikingly alike in the two species. In the perichaetial bracts of 
Hf, uncinata, certain of the foliar characters become accentuated 
while others disappear. The margin of the lobe, for example, is 
much more toothed than on ordinary leaves, but the apex is 
rounded or obtuse instead of being extended as a filiform point. 
Even when a tooth is present at the apex, it cannot be distin- 
guished from the neighboring teeth. The distinctly toothed 
bracts and bracteoles and the dentate or spinose wings on the 
keels of the perianth are also good differential characters in sepa- 
rating the species from H. sudacuta. 
Harpalejeunea heterodonta sp. nov. 
Pale green, scattered among other epiphyllous hepatics : stems 
0.06 mm. in diameter, prostrate and closely adherent to sub- 
stratum, irregularly branched, the branches obliquely to widely 
spreading : leaves distant to subimbricated, the lobe widely spread- 
ing (in outer part), plane or slightly convex even in apical region, 
falcate-ovate, 0.35 mm. long, 0.2 mm. wide, gradually narrowed 
into a long-attenuate apex, attached by an almost longitudinal 
line of insertion, antical margin decurrent by a single cell, straight 
Or nearly so and entire near base, then strongly curved and vary- 
ing from irregularly crenulate to spinose, the crenulations being 
, slightly projecting cells and the spines sometimes attaining a length 
. of five cells and a width of three cells at the base, postical margin 
straight or slightly curved, obscurely crenulate from projecting 
cells, apex commonly terminating in a row of two or three cells ; 
lobule ovoid, 0.17 mm. long, 0.1 mm. wide, strongly inflated, 
abr uptly constricted in outer part thus forming a very short, 
slightly curved passage-way leading into the water-sac, keel 
strongly arched, slightly roughened in outer part from projecting 
cells, free margin straight or nearly so, involute to beyond apex 
then passing by a shallow lunulate sinus to end of keel, apical 
tooth short and slightly curved; cells of lobe plane or nearly so, 
