PLATE 17 



A, B. — Puccinia graminis tritici from Hordeum jubatum (Moorhead, Minn.) on rye 

 after having previously spent 2 urediniospore generations on rye, 4 on barley, i on 

 rye, 2 on wheat, and 5 more on barley. Twenty-one out of thirty -two blades inocu- 

 lated became infected; the uredinia produced were very small and siurounded by 

 hypersensitive areas. 



C. — Puccinia graminis tritici from Hordeum jubatum, originally from Moorhead, 

 Minn., but with subsequent history of R2 — B4 — Rj — Wg — Bg — Rj. (See fig. A.): 

 Normal infection on wheat. 



(250) 



