212 Evans: HEPATICAE OF PUERTO RICO 
more or less closely. They are deeply bifid with long and spread- 
ing divisions, which taper gradually to sharp or blunt apices 
(PLATE 16, FIGURE I; PLATE 17, FIGURES I and 2). Sometimes the 
divisions spread so widely that the upper margin of the underleaf 
is bounded by an approximately straight line. At the base a dis- 
tinct radicelliferous disc is usually developed (PLATE 16, FIGURE 6) 
and affords a firm anchorage to the substratum. The margin is 
practically entire although the cells in some species often project 
as indistinct crenulations. 
So far as known the inflorescence is either autoicous or dioicous 
and seems to be fairly constant for a given species. The arche- 
gonium is sometimes borne on a leading branch (FIGURE 1) and 
sometimes on a very short branch, in many cases a single leaf and 
a single underleaf being the only appendages present except the 
involucral leaves and the perianth (FIGURE 2). The female flower 
seems to be invariably subtended by a single innovation. The 
bracts are much smaller than the ordinary leaves and are sub- 
equally bifid (FIGURE 7), the lobule sometimes slightly exceeding 
the lobe in length (PLATE 16, FIGURE 17, on left). The single 
bracteole is free and more or less bifid, the divisions sometimes 
spreading widely and sometimes being suberect or connivent 
(PLATE 16, FIGURES I and 11). The perianthis sharply five-keeled, 
although more or less compressed, and becomes suddenly co? 
tracted at the apex into a short beak. The surface is apparently 
never roughened by teeth or projecting cells even along the keels. 
The antheridial spikes (PLATE 17, FIGURE 2) are much as in other 
Lejeuneae. They either occupy short branches or are terminal 0m 
longer branches and rarely show signs of proliferation. The bracts, 
which are rarely numerous, are usually diandrous. The sporo- 
phyte is essentially the same as in Cololejewnea and the other 
genera of the Lejeuneae. 
The only species of Diplasiolejeunea that has been recorded 
from Puerto Rico is the type species, D. pellucida. The material ; 
collected by the writer includes this species and also three othe 
one of which seems to be undescribed. In distinguishing ae 
species the lobules, the underleaves, the inflorescence, 4% gs : 
perichaetial bracts yield the best differential characters: ne - 
gemmiparous branches and the gemmae, which will be des? 
at the close of the paper, may likewise be of service. 
