45° BOTANICAL GAZETTE [JUNE 
Miss McCormick (7) has shown in Symphyogyna that the spore 
mother cells assume an amoeboid form in connection with the 
development of the 4 lobes which characterize the spore mother 
cells of the Jungermanniales, and the same behavior has been 
observed in Pallavicinia (4). The assumption of an amoeboid 
character by the young spore mother cells of Reboulia, in which 
no lobes develop, clearly demonstrates that this behavior is not 
necessarily related to the formation of lobed spore mother cells. 
With the gradual dissolution of the old spore walls, the spore 
mother cells lose their amoeboid form and become globular, grad- 
ually growing larger and becoming increasingly more dense by the 
accumulation of food material (figs. 14, 15). Thus the writer is 
inclined to regard the amoeboid development as a feature related 
to the nourishment of the spore mother cells. Their increase in 
size and globular form is certainly not due to the release of pressure 
upon the cells of the sporogenous tissue occasioned by the increased 
size of the capsular cavity, for no such enlargement or acquisition 
of food material is shown by the elaters. 
The mucilaginous substance around the spore mother cells and 
elaters presents a foamlike appearance as these changes are going 
on, and becomes increasingly less dense. Both the spore mother 
cells and elaters form a new cellulose wall after the former have 
reached their maximum size (fig. 15). ‘The new spore wall around 
the spore mother cells becomes thick and is differentiated into a 
thin intine and a heavy exine. Their protoplasts are now extremely 
dense, so that even in sections cut to a thickness of 3 y it is very 
difficult to study nuclear details. 
With the development of the walls in the spore mother cell to 
form the tetrad, a thin epispore is laid down (fig. 16). The elaters, 
which elongate considerably as the spore mother cells develop, have 
merely a thin cellulose wall when the tetrad stage in sporogenesis is 
reached, and their protoplasm is slightly withdrawn inside of the 
cell cavity. 
With the separation of the spores from their tetrads, all of the 
mucilage is gone. The epispore develops prominences by a process 
of outbulging (fig. 17), so that the mature spore when seen from 
the surface is described as having a thick ‘tuberculate’’ epispore- 
