1916] 
GILMAN—CABBAGE YELLOWS 95 
In one other member of the Fungi Imperfecti, Sphaeropsis 
Ellisii, Petri (713) has observed that the attack was depend- 
ent on cool humid atmospheric conditions, and the fungus was 
never seen in warm well-ventilated exposures. 1t is probable, 
however, that in this disease the limiting factor is moisture 
rather than temperature. 
Basidiomycetes.—The temperature relations of the smuts 
and the rusts have been worked out more exactly than the 
other Basidiomycetes. Brefeld (795), in experiments with oat 
smut (Ustilago Avenae), showed that when germinated spores 
were placed in soil and oats grown therein, 27-30 per cent 
of the plants became infected at 15^C., while at 7°C. 40-46 
per cent were attacked. Tubeuf ('01), working with the same 
form, found the opposite results when ungerminated spores 
were used instead of germinated. He showed also that the 
spores of Ustilago Avenae cannot germinate under 5°C., their 
minimum for germination being between 5 and 9°С. As is 
pointed out by Hecke (709), the п im the findings is 
probably due to the fact that Brefeld germinated the spores 
before exposing the cultures to the different temperatures 
while Tubeuf did not. On account of this difference the time 
of susceptibility of the host was lengthened by the low tem- 
perature in Brefeld’s experiments, and hence the increased in- 
fection; while in the experiments of Tubeuf the plants at low 
temperatures were held below the temperature of germination 
of the smut spores, and, therefore, the greater infection oc- 
curred at the higher temperatures. 
In regard to the stinking smut of wheat (Ustilago Tritici), 
on the other hand, the minimum temperature for germination 
of both the wheat kernel (3-4°C.) and the spores of the fun- 
gus (5°C.) was practically the same, while the maximum for 
the smut germination (25°C.) was considerably lower than 
that of the wheat (30—32*C.), so that in this ease the opposite 
facts were true, as Hecke (709) showed. "Therefore, the in- 
fection was favored by low temperatures and prevented by 
high (25°C.), because when the plant grew slowly the length 
of the susceptible period was increased. Munerati (712) re- 
ports similar observations on wheat in Italy; early fall and 
