DEVELOPMENT OF PYRONEMA CONFLUENS VAR. INIGNEUM 29 1 
crops as in the first one. This may have been due to differences in the 
two rooms or to some other factor; but it seems hardly Hkely that it 
was connected with conditions of steriHzation, since the pot on which 
the fungus was growing had been kept moist for more than five months 
before the fungus appeared. This is more probable since Seaver ('08) 
found that keeping soil moist for a week destroyed the beneficial 
effects of sterilization. The pot was set aside early in June and 
allowed to dry. It was again watered about the first of the following 
October. Ascocarps were produced steadily during the next six weeks 
after which the fungus was attacked by small beetles and disappeared. 
It will be seen that the last ascocarps were produced more than twelve 
months after any possible sterilization. 
During the fall of 1909 the form of Pyronema confluens described 
by Seaver ('09) was grown in the same room and on pots similar to 
those on which the variety inigneum had been grown the previous 
fall. In no case was more than a beginning of growth obtained on 
pots which had not been sterilized or which had been kept moist for 
more than a week after sterilization, while in every case in which the 
soil was moistened and inoculated, immediately after sterilization,, 
ascocarps were produced in large numbers. These experiments, con- 
firming as they do those performed by Seaver, seem to show that 
sterilization produced some change in the substratum which was 
essential for the growth of this strain. The growth of the variety 
inigneum seemed, however, to be quite independent of sterilization 
for it is hardly possible that any of the beneficial effects of sterilization 
should remain in a pot after twelve months, during eight of which it 
had been kept moist, thus allowing the growth of fungi and various 
micro-organisms. Although the two forms were grown at different 
times, the use of similar pots in the same room and at the same season 
of the year with such decidedly different results, in the two cases, 
would seem to show that the forms are quite distinct physiologically. 
Development 
The ascocarps which were produced on the pots were formed on 
the surface of a mass of hyphae which frequently grew over a felt of 
Penicillium. Owing to this method of growth, ascocarps of all ages 
could be removed from the pot with a sharp scalpel without injury. 
That this was the case was shown by an absence of any signs of dis- 
placement or tear'vng in the specimens. The material was killed in 
