78 College of Forestry 
these cells being retained for a time within the walls of the 
original hyphal filament. If such a filament is mounted dry 
on a glass slide and viewed through the microscope, the 
empty membranes between the oidia appear to have collapsed 
as shown in Plate XIV, Fig. 2, a. At a still later period, 
the divided filament disintegrates, setting free cells with 
rounded ends of all shapes and sizes (Plate XIV, Fig. 2, b), 
most of them being short cylindric bodies varying from 
7-25 vu in length and possessing dense refractive contents. 
re the formation of oidia, both the primary and secondary 
types of mycelium are equally. active, although the oidia 
usually are not formed directly from the hyphe provided 
with clamp connections, but from smaller branches of the 
size and appearance of the primary hyphe. The retention 
of vitality by this secondary spore form was not tested as 
was done with the primary spores — the basidiospores. 
07, p..149), however, states thot the + 
vitality by nine is short, and it is reasonable to suppose that 
these asexual spores are of less vitality than the basidiospores 
which probably are of sexual origin. 
Recently formed oidia of Pol yporus pargamenus were 
found to germinate readily upon being transferred to hang- 
ing drop cultures. The germination of the oidia was fol- 
lowed in as much detail as was that of the basidiospores. 
Oidia transferred from pure cultures on agar plates to hang- 
ing drop cells containing sugar-wood decoction were found to 
germinate in about the same time required for the basidio- 
spores, and always in less than twenty-four hours. Most of 
the oidia germinated at first from one end only; occasionally, 
however, germ tubes were put forth simultaneously from both 
ends. In case only a single germ tube was put forth, a second 
one was later put forth from the remaining end, although 
it did not follow as quickly as was the case in the basidio- 
spores, and usually there was considerable growth of myce- 
lium before germination occurred from the other end. Three 
successive generations of oidia were secured in hanging drop 
cultures by. isolating the oidia when formed and transferring 
them to new hanging drop cells. Evidently the process of 
