April, 1921] Powdery Mildews of Ohio 215 



Uncinula macrospora Peck. 



Butler and Hamilton Counties. Also collected in the first 

 county by Freda M. Bachman and W. G. Stover. Ususally found 

 on elms in Ohio. 



Uncinula necator (Schw.) Burr. 



Butler and Hamilton Counties. Also collected in the first 

 county by Freda M. Bachman and E. E. Duncan. This mildew 

 sometimes damages grapes considerably. 



Uncinula parvula Cooke & Peck. 



Butler County. Also collected here by E. E. Duncan. On 

 Celtis occidentalis . Not previously reported from Ohio. Known 

 only in North America and on members of the genus Celtis. 



Uncinula salicis (DC.) Winter. 



Butler and Lake Counties. Also collected in the first county 

 by Freda M. Bachman, W. G. Stover, and E. E. Duncan. A 

 beautifully zonate condition, not otherwise known to me, was 

 collected on a species of Populus in Lake County. Unfortunately 

 the zonation has disappeared in the herbarium. Well known in 

 Ohio, and confined mainly to the Salicacece. 



Podosphaera oxycanthe (DC.) de Bary. 



Butler County. Also collected here by W. G. Stover. Pre- 

 viously collected in Ohio from several localities and on three 

 or four hosts. 



Microsphaera alni (Wallr.) Salm. 



Butler, Highland, Ross, and Montgomery Counties. Also 

 collected in the first county by Freda M. Bachman, W. G. 

 Stover, E. E. Duncan, and J. R. Wright. Probably the best 

 known mildew in Ohio. Common on Syringa vulgaris and found 

 on many other hosts. A variable and confusing species. 



Microsphaera alni vaccinii (Schw.) Salm. 



Butler County. Reported from a few other localities in 

 Ohio, with species of Vaccinium and Catalpa as hosts. 



Microsphaera diffusa Cooke & Peck. 



Butler County. Collected here also by Freda M. Bachman 

 and E. E. Duncan. On Symporicarpus vulgaris. Recorded for 

 Ohio from several other localities and on other hosts. 



