Evans: HEpATICAE OF PUERTO RICO 45 
ing of a single projecting cell, or it may be longer and prolonged 
into a straight or curved row of from two to four cells. Frequently 
the tooth is bent inward toward the lobe. The hyaline papilla is 
situated in the vicinity of this tooth but is displaced several cells 
from the margin on the inner surface of the lobule (FIGURE 6). In 
addition to the apical tooth the free margin sometimes bears from 
one to three accessory teeth between the apex and the base (FIG- 
URES 3, 16), but these vary considerably in size and degree of dis- 
tinctness even when normally present and in some species are ap- 
parently absent altogether. The leaf-cells are essentially like those 
of Symbiezidium (FIGURE 4), but the local thickenings of the walls 
are sometimes very indistinct. The underleaves are also very 
much alike in the two genera. 
The female inflorescence in Marchesinia is borne on a leading 
branch and normally innovates on both sides (FIGURE 1), the inno- 
vations varying greatly in length and often being limited in growth 
by the development of new inflorescences. Ina few of the species, 
however, of which 1. Mackaii is a striking example, double inno- 
vations are the exception rather than the rule, most of the flowers 
innovating on only one side. The lobes of the bracts are similar 
to those of the foliage leaves but tend to be narrower and more 
strongly dentate (FicuRES 7, 8, 11, 12, etc.). The lobules are dis- 
tinct but vary greatly in form, size, and marginal characters, a 
considerable degree of variation being sometimes observable on 
an individual plant (FIGURES 14, I5). The bracteoles are free and 
mostly oblong to obovate in outline ; they are frequently toothed 
(FIGURES 9, 13, 20) and sometimes distinctly bifid (FIGURE 21). 
The perianth is one of the most characteristic features of the 
genus. It is strongly compressed and broadly oblong or obovate 
in outline (FIGURE I). The apex is truncate or slightly retuse with 
tounded outer angles and bears a distinct beak. The postical keel 
is low and scarcely discernible, and there are no teeth either on 
the sharp lateral keels or on the postical surface. In many re- 
‘pects the perianth resembles that found in Stictolejeunea, but there 
are never distinct auricles at the upper angles. 
The male inflorescence is usually terminal on a more or less 
elongated branch and bears bracteoles throughout its entire length. 
The bracts are imbricated and bear the antheridia singly or in 
