560 Evans: HeEpaTICAE OF PUERTO RICO 
agree essentially with those found in Stictolejceunea.* In other 
words, each normal vegetative branch represents the postical half 
of one of the lateral segments cut off from the apical cell (PLATE 
33, FIGURE 13), while each sexual branch, either male or female, 
represents a portion only of such a half-segment (FIGURE 16). 
When flagelliform branches are produced these agree with the 
sexual branches in origin, arising behind leaves with lobules. 
The leaves present a very different appearance according to 
whether they are dry or wet. When dry they are suberect and 
strongly convex, tending to be closely imbricated and wrapped 
about the axis. When wet they spread widely from the axis and 
become more nearly plane, although the postical margin usually 
remains more or less revolute (FIGURES 13, 16). The lobes are 
falcate from a cordate base (FIGURE 14) and are approximately 
ovate in outline, being distinctly narrowed in the outer part. The 
apex is acute and the margin more or less serrate, the teeth being 
sometimes restricted to the apical region and sometimes extending 
well toward the base. These teeth vary greatly in size, but are 
usually sharp and coarse, resembling those found in 7 hysananthus. 
The lobule is less definite in structure than in most genera 0 
the Lejewneae and sometimes consists of little more than a dilation 
at the postical base of the lobe. Even when well-developed it is 
attached to the axis by an exceedingly short line, from which it 
expands abruptly. The free margin is involute near the base and 
more nearly plane in the outer part, the sinus passing gradually 
into the postical margin of the lobe. In this way a rudimentary 
water-sac is formed at the base of the lobule with a broad opening 
leading into it. In some cases the sac opens directly into the 
revolute portion of the lobe. The hyaline papilla is unusually 
large but tends to disappear early on account of its fragile nature. 
It is situated on the free margin a short distance beyond the middle 
(FIGURE 20). In certain species there is neither indentation nor 
tooth to mark its position ; in other cases there is a rounded ang'€ 
which is proximal in position to the papilla. This angle evidently 
eh ea the apex of the lobule and marks the beginning of the 
sinus. The papilla may therefore be considered as distal to the 
apex. 
* See Evans, Bull. Torrey Club 34: rs 1907. 
ER ease ee 
