916 
Journal of Agricultural Research 
Vol. XXVIII, No. 9 
There is as yet insufficient evidence to explain why perithecia have been ob¬ 
tained only where two‘strains have been planted together. Heterothallism is the 
first interpretation to present itself. Another possibility is that it is a case of 
chemical stimulation of one strain by the other. As bearing on the latter possi¬ 
bility, Heald and Pool (10) report that Fusarium moniliforme produces metabolic 
products which have such a stimulating effect on an entirely different fungus. 
They grew it with Melanospora pampeana £|peg. with the result that the latter 
fungus was stimulated to produce perithecia. It is hoped that investigations 
in progress may yield contributions along these lines. 
