Apr. ag, 1918 



Stemphylium Leaf spot of Cucumbers 



303 



Fig. 2. — Spore germination of Stemphylium cucurbitacearum: A-E, various stages in the germination of 

 a single spore in nutrient bouillon. A , 6 hours; B, 8 hours; C, 12 hours; D, 24 hours; E, 36 hours. X 105. 

 F-G, same as A~B, but more highly magnified, showing origin of germ tubes. X 1,190. H, spore ger- 

 minated in nutrient bouillon after 48 hours. X 105. /, spore germinated in distilled water after 48 hours, 

 showing thin- walled vesicular bodies. Xios. J, portion of the germ tube shown in / more highly 

 magnified. X 1,190. 



The maturity of the spore has nothing to do with its capacity for 

 germination. In Plate 24, A, is shown a germinating spore which has 

 not yet begun to turn brown. The writer has secured germination from 

 the earliest stages of spore formation. 



