8 BOTANICAL GAZETTE [JULY 
arises on the inner and anterior side of the leaf, just above the 
axillary bud which is always present. As in Marsilia, a fertile 
branch of the stem has a sporocarp on nearly every leaf, but | 
there is never more than one on the same leaf in Pilularia, or 
could any rudiment of a second be found. 
The young sporocarp owes its origin to the formation of a 
two-sided apical cell in one of the marginal cells of the fourth 
grade in (probably) the first segment of the anterior side of the 
leaf (7, fig. 72). The difficulties of orientation were such that 
transverse sections of the leaf in this region were not frequently 
obtained, and it cannot be definitely stated therefore that the 
Sporocarp arises in the quaternary marginal cell, rather than the 
tertiary one, but the evidence obtained seems in favor of the 
former. The fusion of the outer tissues of the leaf with the 
stem makes it impossible also to state positively from which 
segment the sporocarp arises, but I believe it to be the first 
rather than the second, and certainly it cannot be a younger one 
than this. “ 
The apical cell of the sporocarp has its longer axis across the 
leaf, and cuts off se : 
readily seen 
The fate 
is at first ex 
Z7), but wh 
