PLATE 3 
Effect of cold water extract from dry outer onion scales upon spore germination 
of Colletotrichum circinans. 
A. —Photomicrograph of spores about 17 hours after being placed in an extract 
from the yellow scales. Note the masses of naked cytoplasm which have exuded 
from the spores after the tip of the young germ tubes have ruptured. Compare with 
fi. 
B. —^Photomicrograph of spores about 17 hours after being placed in an extract from 
white scales. Note the normal germ tubes and appressoria. Compare with A. See 
also figure i and further explanation in the text. 
