1 8 Evans . — Branching in the Leafy Hepaticae . 
Zoopsis . — Among the genera which Spruce (’82) included under Cepha- 
lozia , branching of the type now being discussed seems to be exceedingly 
rare. It has been reported, in fact, in scarcely a half-dozen species, two of 
which belong to the genus Zoopsis and the others to the genus Cephalozia 
in its restricted sense (the subgenus Eucephalozia of Spruce). In Zoopsis 
Leitgeb (’76) alluded briefly to the branching and stated that only vegetative 
branches ever conformed to the Frullania type. His observations were 
largely based on Z. argentea> a widely distributed species the range of which 
extends from New Zealand and Australia into tropical Asia. The leaves in 
this species are probably the most rudimentary found in the genus (Fig. 24). 
Each consists of only four cells, two of which form the base. The other two 
cells are in the form of papilla-like appendages attached more or less trans- 
versely to the basal cells, the one belonging to 
the more dorsal cell being about twice as long 
as the other. Although at first sight the leaves 
appear longitudinally inserted, they are really 
very slightly succubous. The underleaves are 
minute, but are apparently always present. In 
the figure the branch is on the right-hand side, 
and it will be seen that the leaf belonging to the 
same segment consists of only two cells, the 
long apical papilla indicating that the dorsal 
half is the one represented. It should also 
be noted that this incomplete leaf seems to be 
situated at the base of the branch instead of 
on the branching axis. Aside from this pe- 
culiar leaf there is little to show that the branch- 
Guinea (L. Lorfa/Nof^)^* x* 8a system is not a dichotomy, the first leaf of the 
branch being normal in structure and position 
and the first underleaf (not shown in the figure) being ventral and like 
the other underleaves of the plant. 
Cephalozia . — The Frullania type of branching has been noted by 
Leitgeb (’75) in C. bicuspidata and C. cnrvifolia , by Spruce (’82) in C. tubu- 
lata , and by Stephani (’06-’09) in C. hamatiloba and C. asperrima. Only 
the first two of these species will be considered here. They are both widely 
distributed in Europe, Asia, and North America. In C. bicuspidata Leitgeb 
calls attention to the undivided leaf at the base of a branch and notes 
that he has observed branching of this type in but a single instance. 
Apparently, however, the phenomenon is less uncommon than he implies. 
The writer has found it to occur not infrequently in specimens from British 
Columbia collected by Macoun and by Brinkman, and also in a specimen 
from Baden collected by Jack and distributed in Gottsche and Rabenhorst’s 
Hepaticae Europaeae (No. 353). In Fig. 25, which represents one of 
