1921] HOERNER—GERMINATION 177 
23 days, during which period the maximum temperature was 86°F. 
and the minimum 29°F 
6. Kept in the dark, urediniospores at similar temperatures to 
those exposed to light, remained viable as long as 79 days. 
7. Urediniospores germinated at a temperature as low as 7°C., 
with an optimum of 18°C., and a maximum of 32°C. 
8. Teliospores developed on oat seedlings in the greenhouse and 
not afforded a period of overwintering did not germinate. 
g. Previous to overwintering and as late in the spring as May 2, 
teliospores developed in the field were incapable of germination. 
OREGON AGRICULTURAL COLLEGE 
CORVALLIS, OREGON 
