On Helianthus divaricatus, Sunflower. Burl., Sept. 1897; O. 799. 

 On Helianthus laetiflorus. Charlotte, Sept. 1897; O. 798. 

 On Helianthus tuberosus, Jerusalem Artichoke. Newfane, Aug. 

 1892; G. 800. Burl., Aug. 1898 ; O. 1910. 



On Solidago Canadensis, Golden Rod. Burl., Sept. 1897; O. 794. 

 Beaver, Sept. 1897; O. 793. 

 On Verbena hastata, Blue Vervain. Beaver, Sept. 1897; O. 788. 

 On Verbena urticasfolia, White Vervain. Burl., Sept. 1897; O. 789. 



Cicinobolus Cesatii DeBy. frequently occurs parasitic on this fungus 

 on various hosts. 



Erysiphe communis (Wallr.) Fr, 



On Amphicarpaea monoica. Burl., 1890; J. 801. 



On Aquilegia vulgaris, Columbine. In Herb. A. J. Grout. 



OnClematisVirginiana, Virgin's Bower. Beaver, Sept. 1897 ; 0.802- 



On Delphinium alpinum. Larkspur. Charlotte, Sept. 1897; O.803. 



On Lupinus perennis, Lupine. Burl., Aug. 1897; O. 804. 



On Oenothera biennis. Evening Primrose. Burl., Oct. 1890; C. 807. 



On Pisum sativum, Pea. Burl., Oct. 1891; J. 805. No. Calais, 

 Aug. 1898; O. 1900. 



On Ranunculus acris, Buttercup. Burl., Aug. 1890; C. 810. New- 

 fane, Aug. 1892; G. 808. 



On Thalictrum dioicum. Meadow Rue. Beaver, Sept. 1897; O. 811. 



On Viola blanda, Violet. Beaver, Sept. 1897; O. 812. 



Erysiphe Graminis DC. 



On Agropyron repens, Witch-grass. Beaver, Sept. 1897; O. 815. 

 Burl., May, 1898; O. 1369. 



On Poa pratensis, Kentucky Blue-grass. Burl., Oct. 1890; C. 814. 

 On Poa serotina, Fowl Meadow-grass. Burl., June, 1898; O. 1785. 

 On Poa sp. Winooski, Oct. 1890; C. 813. 



Very common. On witch-grass it is brownish gray and quite downy. 

 Rather injurious. 



MiCROSPHiERA Alni (DC.) Wint. 



On Alnus incana, Alder. Burl., 1891 ; C. 813. Winooski, Oct. 

 1890; C. 814. 



On Betula lutea. Yellow Birch. Newfane, Sept. 1892; G. 816. 

 Beaver, Sept. 1897 ; O. 817. 



On Ceanothus Americanus, New Jersey Tea. Burl., Sept. 1897; O. 

 818. 



On Cornus alternifolia, Dogwood. Newfane, Aug. 1892; G. 819. 

 Beaver, Sept. 1897; O. 820. 



On Corylus rostrata, Hazel-nut. Burl, Aug. 1897; O. 821. 



