DETAILED ACCOUNT OF SPECIFIC DISEASES OP PLANTS St$ 



The oogonia and antheridia are not so common as the conidiospores. 

 If the shriveled parts of the leaves are examined in September, the 



Fio. 1 86. — (irape leaf attacked by mildew, Plasmopara vilicola, Cold Spring Harbor, 



L. I., Aug. 2, 1915. 



oogonia will be found as spheric organs attached to the intercellular 

 hyphae by a short stalk. One or several filamentous curved antheridia 

 are formed near the oogonia to the surface of which they become ap- 



