1921] 
WEBB—GERMINATION OF SPORES OF CERTAIN FUNGI 323 
than in the case of other included forms, these fungi are more or 
less similar in behavior. The results obtained in the various 
culture solutions are consistent and comparable. Certain 
stimulating effects, it will be noted, are exhibited by the neutral 
cultures of the beet decoction, but the favorable range in this 
medium does not expand as it does for certain of the other 
fungi. Meacham (’18) obtained inhibition of growth of L. 
saepiaria at approximately Py 1.7 in synthetic media and malt- 
extract, and it is of interest to note that he frequently obtained 
/n 
4, 
* 
ze 
E 
d | INY. Z/N ` 
: i / NS a 
i dj = 
Boi j , X 
wil 
Percentage f Germination 
A 
o 
ee | 
a. 
~~ 
— 
] 
Ay 1 2 3 +4 s 
Fig. 28. Puccinia graminis in Czapek’s full nutrient solution. 
a maximum of growth at about Py 3.0, which approaches very 
closely the hydrogen-ion concentration in the mannite, Czapek, 
peptone, and beet decoction solutions which afford maximum 
germination. 
The uredospores of Puccinia graminis do not germinate, on 
the whole, in solutions with as high hydrogen-ion concentrations 
as some of the other fungi employed, the favorable range ter- 
minating between Py 2.5 and 3.0 as compared with Py 1.5 to 2.0 
in other cases. Relatively low percentages of germination are 
obtained under conditions of active alkalinity, except in the 
case of “water HCl or KOH,” and such percentages vary 
materially with the medium. In “water HCl or KOH,” 
germination occurs freely at Pa 9.4, a hydrogen-ion concentra- 
tion producing inhibition of germination with the other media. 
