142 BOTANICAL GAZETTE [AUGUST 
apples. Such naturally formed appressoria are shown in jigs. 5, 6, 
while in fig. 7 a single adhesion organ is shown in section. 
CONCLUSIONS. 
The spore-like organs formed by the germ tubes of the anthrac- 
noses are adhesion organs, by means of which the fungus is attached 
to the surface of its host during the early stages of infection. They 
are not suited for dissemination and therefore are not to be regarded 
as spores. The adhesion discs are formed as a result of stimuli 
from mechanical contact acting on the germ tubes. When growing 
in nutrient media the germ tubes lose their power of reacting to 
contact stimuli by the formation of appressoria. Under natural 
conditions the appressoria are formed as soon as the germ tube 
emerges from the spore. 
Notr.—In the same year ATKINSON describes these bodies for a species of 
Colletotrichum (C. Gossypii)'5 and suggests that their production in unfavorable 
conditions seems to favor the notion that they are resting bodies. 
1s ATKINSON, G. F., Anthracnoses of cotton. Journ. Mycol. 6:173-8. pls. 2. 2, 1891. 
THE UNIVERSITY OF CHICAGO. 
