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several blocks in every direction had rust upon it, the amount grad- 

 ually becoming less. Timothy and red top in the vacant lot also 



Fig. 51. — Relation of Barberry to rust on grasses at Waukon. 



were badly infested, the rust on timothy occurring on leaf and stem. 

 It seemed to me a very clear case of the influence of the cccidium of 

 the barberry on the rust on grasses. There were plenty of old aecia 



