Evans: HEpPATICAE OF PueRTO RIco 185 
papilla instead of being marginal is situated on the antical surface of 
the lobule at some little distance from the margin (FIGURE 6), very 
much as Leitgeb describes for ““Phragmicoma.’* A somewhat simi- 
lar lobule is found in Brachiolejeunca and also in some of the 
species of Marcehesinia, but it is very different from that found in 
Cycloleyeunea and Prionolejeunea. The leaf-cells in Odontolejeunea 
are plane or nearly so and their thin walls are firm and frequently 
pigmented. Trigones and intermediate thickenings, although small, 
are everywhere conspicuous (FIGURE 3), but there are no ocelli. 
The underleaves in Odontolejeunea are approximately orbicular 
in shape and are commonly described as auriculate at the base. 
The latter character, however, does not accurately portray the 
true conditions, because in reality the strongly auriculate appear- 
ance is due to the peculiar way in which the underleaves are at- 
tached to the axis. The line of insertion is long and sharply 
arched, and the basal part of the underleaf broadens out so 
abruptly from this line that it becomes folded upon itself, the fold 
forming what is apparently the inner edge of a large basal auri- 
cle (FIGURE 2). In many cases the lower margin of the underleaf 
does not extend at all beyond the line of insertion, and of course 
under these circumstances there is no true auricle whatever; in 
other cases a slight auricle is developed. The margins of the 
underleaves are more or less toothed. The radicelliferous discs 
are highly developed and normally give rise to rhizoids not only 
from their margins but also from their postical surface. On ordi- 
nary underleaves the marginal rhizoids are in a single layer and 
are more or less palmately branched at their extremities. All of 
the rhizoids secrete an abundant supply of a tenacious jelly-like 
substance, a peculiarity possessed by the majority of epiphyllous 
Lejeuneae. 
The position of the © inflorescence is variable even in the 
Same species, being sometimes borne on a leading branch and 
Sometimes on a short branch. The inflorescence innovates on 
One side and frequently the innovation itself is repeatedly flori- 
ferous. The lobules of the bracts are represented by minute basal 
folds (riGuREs 8, g) and the bracteole is undivided (FicuRE 10). The 
oie ee iis Paiste ona 
* Unters, iiber Lebermoose, 2: 14. 1875. Apparently the “ studied was P. 
Mackaii (Hook. ) Dumort. ( = Nerviesteta Mackati S, F. Gra 
