36 C f c r the same period. Similar illustrations for Diplod 

 after 3 days are shown in figure 10. Toe Is.rrer hyphae (a) 

 with uniform diameter and regular h ranching was grown with a 



temperature of 23°C. , while the other, (t), with irregular 



"branching, peculiar swellings and densely granular contents, 



o 



was prown with a -maintained temperature cf 36 C. Seme of 



the cells formed with the richer temperature appeared to v e 

 nearly or cuite devoid of protoplas • The drawings of figure 



10, (h) also represents the usual appearance of Diplodia hyphae 



o c 



after one day at 45 , and after two days at 40 C. Growth was 



discontinued after these periods with these temperatures. 

 Cultures of the ether two fungi for maintained temperatures of 



32° and 34° C showed much the same irregular and densely grardu- 

 lar filaments as those illustrated for Phytophthora and Dipl - 



dia with higher temperatures. 



Turning to the structural characteristics of cultures 

 grown with very low temperatures, which approached the tempera- 

 ture minimum for enlargement, with the lowest maintained tem- 

 perature tested for Pythiacystis and Phytophthora (7.5 C C) the 

 hyp'nal diameter was much greater than with temperatures wit 

 in the favcrahl© temperature range. The hyphal contents for 

 these low temperature cultures was only slightly grandulara 



Sample filiments representing 4 day culture of PytMacytia 



o o 

 with maintained temperatures of £3 and 7.5 C. are shown at 



a and c, figure 8, and the same comparison for 4 day cultures 

 of Phytophthora may be made by means of drawings shown at a 

 and c, figure 9. The J.ow temperature filiments of Pythiacytis 

 are much swollen and divide into many short, thick club-shaped 

 branches, and those of Pythophthora show a series of swollen 



