1909] STEVENS & HALL—VARIATION OF FUNGI dy 
V. Unknown factors 
ASCOCHYTA CHRYSANTHEMI STEVENS 
This fungus frequently exhibited differences in character along 
different radii of the same colony, the conditions of medium, thickness 
of sowing, humidity, etc., being apparently identical. 
Fig. 12 shows suchacolony. Along the radius aa, at b, the colony 
bore pycnidia abundantly, and the mycelial progeny of this strain 
extending to the periphery of the colony was rich in pycnidia, while 
Fic. 12.—A scochyta Chrysanthemi Stevens, showing abundant pycnidia on radius 
aa, at the point b, and paucity of pycnidia elsewhere 
most other radii of the colony were sterile or nearly so. Transfers 
were made from the point c (sterile) and d (pycnidial) to fresh plates. 
The sterile mycelium produced a colony which was sterile through its 
early days. As it aged it formed a few large pale pycnidia. The 
fertile strain produced a fertile colony with very numerous, though 
