Evans: HEPATICAE OF PUERTO RICO 261 
in the form of trigones only, but intermediate thickenings also 
are present in certain species (FIGURE 11). The local thickenings 
may likewise form hyaline warts or spinules on the free outer 
walls of the cells, usually one in the middle of each cell. In 
certain species the leaf cells show a higher degree of differentiation 
than in Cololejeunea. Ocelli, for example, may be present or the 
cells along the margin may become empty and hyaline (FIGURE 12). 
The stylus, so far as known, consists either of a hyaline papilla 
or of a slender filament variable in length. 
An autoicous inflorescence seems to be the usual type in Lepto- 
colea, but in rare instances it may be dioicous, paroicous, or even 
synoicous. The branch bearing the female inflorescence varies 
greatly in length but is often much abbreviated (FIGURE 1). It 
always bears one or two innovations and these may sometimes be 
floriferous (PLATE 12, FIGURE 1). The bracts show the same 
characters as in Cololejeunea. The perianth varies considerably 
in different species, although always more or less compressed 
(PLATE II, FIGURES 7 and 16). In some cases a very low antical 
keel and a low two-angled postical keel may be demonstrated, 
but the antical surface is often plane and the postical keel rounded. 
The apex of the perianth is broader than the base and varies from 
rounded to truncate or obcordate. In the last case the short 
beak appears at the bottom of the apical depression. In the 
male inflorescence the bracts are sometimes indistinguishable from 
the leaves (FIGURE 2), but they are often much smaller and have 
relatively larger lobules (FIGURE 3). Certain species, in fact, show 
a wide range of variation in the bracts. The sporophyte is essen- 
tially like that of Cololejeunea. Leptocolea may be briefly char- 
acterized as follows: 
Leptocolea (Spruce) gen. nov. 
Lejeunea, subgenus Colo-Lejeunea, section Leptocolea Spruce, Hep. 
Amaz. et And. 292. 1884. 
Cololejeunea, subgenus Leptocolea Schiffn. in Engler & Prantl, 
Nat. Pflanzenfam. 1°: 122. 1895. 
Plants varying from delicate to robust, pale green, often be- 
coming whitish, yellowish, or brownish with age: stems prostrate, 
irregularly branched: leaves distant to imbricated, the lobe mostly 
