1921] 
WEBB—GERMINATION OF SPORES OF CERTAIN FUNGI 924 
drop or in film cultures of solutions of mannite, sucrose, beet 
decoction, tap water, and distilled water. Previous subjection 
of the spores for various time intervals to low or freezing tempera- 
tures also failed to stimulate germination. 
Marked differences in requirements for germination are shown 
by the spores of fungi. Some are capable of germinating in 
moist air or in water, while others are capable of germinating 
only in the presence of a nutrient solution or special stimulus. 
The percentages of germination, in many cases, depend largely 
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$ I | / Ix \ Y \ 
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cto i | H Neue ee eee l ry \ 
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Fig. 29. Lenzites saepiaria in sugar beet decoction. 
upon the direct food value of the medium; that is, the most 
perfect food affords the best germination. Certain of the fungi, 
however, germinate well in sugar solutions and best in plant 
infusions or decoctions. Such cases, then, may be classed as 
food stimuli. Organic acids are generally regarded as feeble 
stimuli for the germination and growth of fungi, but here again 
the matter is vitally associated with the question of toxicity. 
Taylor (17) determined the concentrations of a few organic 
and inorganie acids necessary to check the growth of various 
organisms. His data led him to conclude that there is a great 
variation in specifieity in the relation of such acids to different 
organisms. 
