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56 MISSOURI BOTANICAL GARDEN. 
nine to twelve days and in fifteen days formed a mass, or crust. 
Five flasks, containing bread-crumbs saturated with potato 
broth, were inoculated February 1, 1912. On February 19, 
the first sclerotia were gathered. Then every three days the 
sclerotia were collected for a period of two months, when the 
medium became exhausted. An average of 512 sclerotia was 
obtained during this time for each culture, a surprisingly 
large number. 
When the first cultures on bread were started, conidia de- 
veloped at once, either before or while the sclerotia were 
forming. However, on making transfers repeatedly, the 
number of conidia became less, while the sclerotia increased 
in number proportionately. Thus cultures were obtained 
with very few conidia, which did not develop until all of the 
sclerotia had matured and the cultures had begun to dry up. 
This condition was noticed in cultures of the fungus 
obtained from several sources. When inoculations were 
made with such conidia on a medium containing little nutri- 
ment, conidia were immediately produced on the mycelium, 
but no sclerotia. It appears, then, that the conidia and 
sclerotia bear a definite relation to one another; that is, the 
formation of sclerotia requires a considerable amount of 
mycelium, whereas the conidia are produced when the 
mycelium is poorly developed and conditions for growth 
are unfavorable. 
Acidity and alkalinity: The best development of the 
fungus took place on a slightly acid medium. A strongly 
alkaline medium retarded growth considerably, causing the 
mycelium to remain sterile. On the other hand, a strongly 
acid medium reduced the number of sclerotia, but favored the 
production of conidia. 
Temperature: Cultures of the fungus on bread-crumbs 
saturated with potato broth were subjected to the following 
temperatures: 37°C., 30°C., 20°C. and 15°C. 
From the results obtained it was clearly evident that a tem- 
perature of 37°C. was unfavorable for the growth of the 
fungus. Growth stopped entirely after progressing a few 
millimeters, no conidia or sclerotia being produced. At 
we 
