The Biology of Polyporus Pargamenus Fries 81 
in hanging drop cultures where a solution of malt extract 
was employed for the nutrient medium, and in cultures made 
on poured plates of malt extract agar. In the former case 
they were observed in cultures made for the purpose of test- 
ing the vitality of shed basidiospores that had been kept in 
a state of dessication for four months. In the latter ease 
the same formations were found in abundance on the sub- 
merged mycelium growing on plates of malt extract agar. 
In both cases they were associated with mycelium that was 
breaking up into oidia and the one illustrated in Figure 4 
depicts the mycelium breaking up into oidia. Nor particular 
significance could be attache -d to these helicoid hyphal for- 
mations. Similar hyphal formations have since been seen 
by the writer on agar plate cultures of Pythium and other 
fungi. 
A portion of a culture on malt extract agar in which the 
mycelium was breaking up into oidia was transferred to 
another plate of the same medium. In the course of the 
next four weeks the developing mycelium spread over the 
surface of the agar and continued to break up into oidia. 
At the margins of the plate, where the agar ended, the myce- 
hum grew up off the agar and formed a white filamentous 
growth i in contrast to the mycelium in contact with the agar 
which habitually broke up into oidia. The filamentous myce- 
hal growth running up the side of the petri dish later became 
yellowish or tawny and began to form a brownish pitted ~ 
hymenium. The beginning of a hymenial formation occurred 
seven weeks after the oidia-forming mycelium had been inoc- 
ulated on the agar plate. Three weeks later the hymenium 
became labyrinthiform. Since the culture was beginning to 
dry out seriously, the fruiting portion was transferred to a 
fresh plate and its growth continued. The mycelium which 
developed out over the surface of the plate broke up into 
oidia while the hymenium exhibited a tendency to become 
hydnoid (Plate XVIII, Fig. 2), eventually appearing the 
same as the previously described ones formed in the flask 
culture of blocks of wood and, like these, also shed copious 
quantities of basidiospores. A number of such transfers, 
