EvANS: HEPATICAE OF PUERTO Rico 271 
therefore, the discussion is restricted to its more important 
differential characters. The relationship of the species to L. 
cardiocarpa is so very close that the leaves and perianths might be 
described in almost identical words. The plants differ markedly, 
however, in their inflorescence, although both are monoicous. 
In L. Jooriana the antheridia are borne, usually singly, in the 
axils of the perichaetial bracts and occasionally in the axil of the 
leaf adjacent to the involucre; in L. cardiocarpa they are borne, 
usually in pairs, in the axils of distinct perigonial bracts, which 
are found on special branches. In consequence of this difference 
there are further differences in the structure of the perichaetial 
bracts. In L. Jooriana the lobules are inflated much as in ordinary 
leaves, while in L. cardiocarpa the lobules are plane. In well 
grown plants of L. Jooriana the lobules of the leaves are relatively 
larger than in L. cardiocarpa, but this difference is by no means 
constant. JL. Jooriana is also characterized by the frequent pres- 
ence of gemmae, while L. cardiocarpa is not yet known to be 
gemmiparous. Unfortunately this is a difference which it is unsafe 
to emphasize until the plants are better known. At the present 
time, therefore, the differences in the inflorescence and in the 
bracts are the only ones that can be relied upon. 
APHANOLEJEUNEA 
So far as known at present, about half a dozen species can 
be referred to Aphanolejeunea with certainty. With the excep- 
tion of the type species, which is known only from the British 
Isles, the genus is restricted to the tropical and south temperate 
regions of America. The type species grows on rocks and on bark, 
often in company with other bryophytes, while most of the 
American species are epiphyllous in habit. All of them flourish 
best in very damp localities, on account of their fragile nature. 
The stems cling closely to the substratum and branch ir- 
regularly. The leaves are usually distant and are never closely 
imbricated. The lobes spread widely and vary in outline from 
oblong or ovate to lanceolate, the apex itself varying from rounded. 
to acuminate (PLATE 12, FIGURES 4, II, and 17). In many cases 
the lobes are distinctly concave on the antical surface. The 
lobules, the structure of which has already been described, are 
