322 DorAN: ON THE GERMINATION OF FUNGOUS SPORES 
temperatures and the range of temperature for germination of 
thirty fungous spores. 
If the optimum temperature for the germination of the spores 
of Plasmodiophora Brassicae, which Chupp (19) found to be 
27°-30° C., is typical for the Myxomycetes, then the temperature 
requirements for the germination of the spores of the slime moulds 
must be higher than those of fungi. 
A study of TABLE I shows for the germination of the spores of 
several groups of fungi the following average cardinal temperatures 
and average range between minimum and maximum temperatures. 
For the germination of the Phycomycetes the average cardinal 
temperatures are 1.2° C., 18° C., and 26.1° C., and the range is 
25.0 degrees Centigrade. For the germination of the aeciospores 
of the Uredinales, the average cardinal temperatures are 6.5 
C., 13.0° C. and 22.0° C. and the average range is 15.5 degrees 
Centigrade. The average cardinal temperatures for the ger- 
mination of the urediniospores are 5° C., 16.2° C., and 28.9° C., 
and the range through which these spores can germinate is 
23.9 degrees Centigrade. In the case of teliospores the cardinal 
temperatures for germination are 7.4° C, 19.9° C., and 28.1° C., 
and the range for germination is 20.7 degrees Centigrade. 
Temperature limits are narrower for the production of sporidia 
by germinating teliospores than for the production of germ tubes 
only. This is illustrated by the results obtained by the writer 
with the teliospores of Puccinia Malvacearum. At temperatures 
as low as 5° C. promycelia are produced but no sporidia. Above 
23° C. promycelia are produced but sporidia are rare. 
These results agree with those of Dietel (29) who found that 
above 23° C. the teliospores of Puccinia graminis produce no 
sporidia but only germ tubes. Reed and Craybill (10) noticed 
that the teliospores of Gymnosporangium Arai sping entering 
do not germinate when the temperature rises to 24° C. But 
above that temperature they sometimes develop promycelia. 
When the Fungi Imperfecti and the one representative of the 
imperfect stage of the Ascomycetes named in Taste I are con- 
sidered collectively, it is seen that for the germination of these 
spores the cardinal temperatures are 7.3° C., 23.1° C., and 
39.6° C. Between the minimum and maximum temperature 
limits for germination ‘here is an average range of 32. 3 degrees 
Centigrade. 
