PLATE 20 



A. — A deformed and partly sterile ear complex produced by a maize plant as a 

 result of downy mildew infection. Notice the branching and elongation of the shank, 

 the abnormal development and arrangement of many of the kernels, and the inclosing 

 of a few kernels in tunicate bracts. The husks have been removed. This specimen is 

 from a Yellow Dent variety that normally has one large and well-developed ear. 



B. — A maize ear developed abnormally as a result of the downy mildew. The husks, 

 beyond which the upper third of the ear protruded, have been partly removed. Save 

 for two or three at the base with partly developed kernels, all the florets were sterile, 

 green in color, and bract-like in texture. Healthy plants of this Yellow Dent variety 

 bear large ears well covered over by husks. 



C. — Ear of a maize plant infected by the do\^^ly mildew. Only a few viable seeds 

 have been formed, the remainder of the florets being poorly developed and sterile. 

 Notice the conspicuous stripes on the leaves. Before the husks were removed the 

 tip of the ear protruded beyond them. Normally this White Flint variety bears long, 

 well-filled ears. 



