46 BULLETIN 380, U. S. DEPARTMENT OF AGRICULTURE. 



At 35° C, Endothia gyrosa, E. singularis, and E. parasitica showed a slight 

 development within 2 days, but at the end of 11 days it was still slight and 

 abnormal in appearance. E. fluens and E. fluens mississippiensis showed no 

 growth at this temperature. 



At 31° C, Endothia gyrosa, E. singularis, and E. parasitica appeared about 

 the same as at room temperature for the first four days. At the end of six 

 days these species showed somewhat less growth than at room temperature, 

 while at the end of two weeks the growth was less in extent and markedly 

 less freshly colored than that at room temperature. E. fluens and E. fluens 

 mississippiensis showed somewhat less growth than at room temperature even 

 in 4 days, and markedly less at the end of 2 weeks. 



At room temperature (which at this time varied from 20° to 24° C.) the 

 growth was much as described in the previous paper. Within 11 days growth 

 was practically complete and in 14 days there was abundant spore production 

 in Endothia parasitica. 



At 18° and 16° C, all species showed considerably less growth than at room 

 temperature, but there seems to be little difference in the comparative growth 

 of the various species at these temperatures. At 13° the growth was decidedly 

 less than at 16° C. but was fairly normal in appearance in all the species except 

 that Endothia fluens mississippiensis failed to produce the characteristic color 

 at this temperature. 



At 9° C. there was a very slight growth in all species. 



At 7°, 5°, and 2° C. there was no growth whatever. Cultures removed to 

 room temperature at the end of 11 days developed normally and at about the 

 same rate as in newly made cultures. 



These additional tests seemed to confirm the results already pub- 

 lished (77, p. 27) ; that is, growth was best in all species at ordinary 

 room temperature, about 20° to 24° C. The minimum temperature 

 for all was about 9°, and all failed to grow at 7° C. The maximum 

 temperature for Endothia gyrosa, E. singularis, and E. parasitica 

 appeared to be about 35°, while the maximum for E. fluens and its 

 variety E. fluens mississippiensis was apparently about 32° C. At 

 all the temperatures tried E. singularis grew much more slowly than 

 any of the other species. 



It was noted that cultures kept at 7°, 5°, and 2° C. showed no 

 growth, but when removed to room temperature developed normally, 

 while cultures kept at 41° and 39° C. failed to grow when removed to 

 room temperature. This seemed to indicate that the fungi are more 

 susceptible to heat than to cold, and such is perhaps the case. There 

 was, however, the additional factor of moisture involved, for while 

 the agar of the cultures kept at 7° and lower was in apparently the 

 same condition at the end of 11 days as when first inoculated, the 

 agar of the cultures kept at 41° to 39° C. was considerably dried. 

 This raised the question as to whether the drying out of the agar had 

 not affected the growth of the fungi in those cultures kept above room 

 temperature as much as the higher temperatures themselves. 



The same idea was suggested by the fact that several of the species 

 grew for a few days at 31° C. as well as they did at room temperature, 

 and then fell behind. It seemed possible that this falling off in the 



