260 Evans: HEPATICAE OF PUERTO RICO 
somewhat more robust than the Florida plants, the leaf lobes 
measuring 0.45 mm. in length and 0.2 mm. in width. The lobules 
unfortunately are all in an exceedingly rudimentary condition, so 
that their typical structure cannot be ascertained. The leaf cells are 
just a trifle larger than in the type, averaging 28 X 16y in the middle 
of the lobe and 16u along the margin. In other respects the vegeta- 
tive organs agree closely. The perianth of the Puerto Rico plant 
is five-keeled in the upper part, indicating pretty clearly that it 
belongs in Cololejeunea. The only perianth present in the type 
material is very immature and is more or less compressed, but it is 
probable that it would present a different appearance when com- 
pletely developed and would perhaps agree closely with the five- 
keeled perianth of the Puerto Rico plant. The gemmae of the 
two specimens are identical in every way. The relationships of 
C. diaphana are discussed in connection with the original descrip- 
tion. 
LEPTOCOLEA 
The genus Leptocolea is considerably larger than Cololejeunea 
and includes about fifty known species. Although almost ex- 
clusively tropical an occasional species is found in temperate 
regions. Most of the representatives of the genus are epiphyllous 
in habit, a few grow on bark, and two or three have been described 
as creeping over other Hepaticae. Apparently none of the species 
grow directly on rocks. Although nearly every species is restricted 
to a particular substratum, this is not always the case, L. cardio- 
carpa, for example, growing on either leaves or bark. The plants 
rarely form pure mats but are usually badly mixed with other 
bryophytes. : : 
The species of Leptocolea tend to be larger than those of 
Cololejeunea, and firmer in texture, but there are many exceptions 
to this rule. Most of the statements which have been made about 
the leaves in Cololejeunea will also apply to Leptocolea. . It should 
be added, however, that the lobes are much more likely to be 
rounded at the apex and that the lobules are relatively smaller 
(PLATE II, FIGURES I and 9). The leaf cells, moreover, exhibit 
a greater variety. In some cases they equal the cells of Colole- 
jeunea in delicacy, but in other cases their walls are thickened, 
either uniformly or locally. Sometimes the local thickenings are 
2 ata sora 
