194 BOTANICAL GAZETTE [SEPTEMBER 
TABLE II—Continued 
FUSARIUM OXYSPORUM AT 30°C. 
Number of days 
I 2 5 6 | 7 9 | To 
aes ame to} 38 I 37.6 | 45.8 | 55.8 | 66. 62.2 
Et ores 8.9 | 5.2 | 17.6 | 19.0 | 40.2 } 77.8 | 62.6 | 69.6 | 78.6 | 66.6 
Average.| 4.9 | 4.4 I 38.9 | 61.8 | 59.2 67. 64.4 
FUSARIUM TRICHOTHECIOIDES AT 25°C. 
Number of days 
CEE EECEEET 
Average...| 4.4 | 19 | 67.4 Jesse] Ree: | eee | ya 202 elves. | Aes 
FusARIUM OXYSPORUM AT 30°C. 
Number of days 
I 2 3 4 | 5 6 | 7 8 | 9 10 
Average. ..| 11.2 | 48 |108.6 | Nene | eeu | eee | eee BADD Vien « hie 
These tables show a tendency of F. trichothecioides to make a 
greater initial growth at low temperatures. At higher tempera- 
tures, however, unless above the optimum of F. trichothecioides, 
F. oxysporum, even though it made the greater initial growth, was 
soon overtaken and passed by F. trichothecioides. This was espe- 
cially marked when dextrose and levulose were used as carbon 
source. This may be the result of a faster though more super- 
ficial feeding of F. oxysporum, which makes it unable to use ma- 
terials as thoroughly as the other organism. This phenomenon is 
hardly a case of more rapid intoxication on the part of F. oxysporum. 
The results obtained with artificial media were verified by 
infection experiments conducted with potato tubers kept at various 
temperatures. Tubers of the Red Cobbler variety were used. 
These were inoculated on April 1, and examined on May 27 
(table IV). See figs. 11 and 12. 
