PLATE 19 



A. — A case of abnormal growth of a maize plant as the result of an attack by downy 

 mildew. The shank h?„s elongated enormously, and an excessive development of 

 the husks has taken place. Only a small, completely sterile ear has formed. 



B. — A maize plant which, when nearly mature, became infected by the downy 

 mildew through a small sucker previously developed. The sucker is obviously in- 

 fected, but the large plant, aside from faint leaf stripings which escape the camera, 

 shows the effect of the disease only in its unexpanded tassel and protruding ear tip. 

 164177°— 20 3 



