16 BOTANICAL GAZETTE [JANUA 
of the pileus from the stipe is, indeed, brought about, in part 
least, by the development of these plates. The first formed gill 
are attached along their entire margin, for atime at least, to th 
guished. It is formed simply as a ridge made up of hyp. 2 
- hyphae in the hymenium of Hypochnus, in something like ¢ 
the hyphae progresses radially inward and downward until t 
width of the mature gill is reached. The branches which 
pushed out right and left terminate their growth almost imme 
ately by the formation of basidia. These basidia intermin 
with sterile cells, which are apparently their morphological eq 
lents, together make up the hymenial layers. In the you 
the hyphae are packed densely together throughout. As _ 
grow older the central cells become separated by intercellu 
Spaces in many cases, and thus form the looser tissue of the tram 
as those which are slightly oblique. Such sections, incli 
few degrees to the long axis of the carpophore, lie in th 
