KUNKEL: SPORULATION IN MACROSPORIUM SOLANI 307 
were obtained in these cultures than when the atmosphere above the 
fungus growth was allowed to remain near saturation. It was found, 
however, that this method of treatment would not bring about very 
abundant sporulation in the case of the early blight organism. A 
number of other methods were tested, and the idea of wounding the 
mycelium was finally hit upon. This seems to be the stimulus neces- 
sary to bring about abundant sporulation in cultures of M. solant. 
It will fruit profusely on any of the media above mentioned if the 
mycelium is thoroughly wounded after the culture is two or three days 
old and has made a good start. So long as the mycelium is undisturbed 
it grows very vigorously through and over the surface of most culture 
media. In these cultures very few conidiophores are produced and 
very few spores are developed. Undisturbed cultures often fail to 
Fic. 1. A wounded hypha bearing conidiophores of Macrosporium solani. 
X 650. 
Fic. 2. A wounded hypha of Macrosporium solani showing the production of 
conidiophores near the point at which the hypha was cut. goo. 
bear a single spore. If, however, the radiating mycelial strands are 
severed at the proper stage in the life of the culture, thousands of 
conidiophores, each bearing a spore, will develop from the cells of these 
hyphae. The wounding may be accomplished by scraping the surface 
of the culture with a sterile scalpel or even with a strong platinum 
needle. The more thoroughly it is done, the greater will be the 
quantity of spores produced. 
Conidiophores arise abundantly near the point at which the 
mycelium is broken. Sometimes each consecutive cell of the mycelium 
for a considerable distance produces one or more conidiophores. Such 
a series of fruiting cells is shown in Fig. 1. At the distal end of some 
