4 Evans: HeEpatTicAE OF Puerto Rico 
points out, is its type of branching. Throughout the /wbuleae the 
branches are invariably lateral and are derived from the postical 
halves of the segments cut off from the apical cell. Two special 
types of branching within the group are however recognized and 
described by Leitgeb.* In the genus Arwd/ania the whole of a 
postical half-segment is used up in the formation of a branch, and 
the leaf which develops from the same segment is therefore desti- 
tute of a lobule. In the majority of the Leyeuneae, on the other 
hand, a portion only of the postical half-segment enters into the 
formation of the branch, and a complete leaf with both lobe and 
lobule develops from the same segment. In the genus Stictole- 
Jeunea both types of branching are exhibited. The ordinary 
vegetative branches are like those found in Frudlania, and the 
leaves subtending them are therefore without lobules (F1GURE 2). 
The male and female branches, however, and the subfloral innova- 
tions are like those found in other Lejeuneae and are borne be- 
hind leaves with lobules (F1icuREs 1, 3). The first underleaf of a 
vegetative branch is very small and is displaced from its normal 
postical position in such a way that the branch apparently springs 
from its axil. The first side-leaf is also small and shows but slight 
trace of a lobule. In the second side-leaf the lobule is already 
well-developed, although the lobe is still small, and the second 
underleaf is normal, both in size and in position. 
Even in its branching, however, Stictolejeunea is not wholly 
unique among the Lejeuneae. In Dicranolejeunea the vegetative 
branches also conform to the /rul/ania type, and the same state- 
ment would apply to the majority of the vegetative branches in 
Ptychanthus and Bryopteris. The first two of these genera agree 
with Stictolejeunea and other Lejeuneae in their subfloral innova- 
tions. The genus /uéula, which may also be mentioned in this 
connection, agrees with Frullania in its vegetative branches but 
produces subfloral innovations and occasionally male branches of 
the Leyennea type. So far as their branching goes, these five 
genera form connecting links between Frullania and the typical 
Lejeuneae. 
The female branch in Stictolejeunea is exceedingly short and 
bears a single leaf and a single underleaf in addition to the bracts 
* Bot. Zeit. 29: §57, 558. 1871. woe 
