The Erysiphaceae of Nebraska 19 



dosa, Boebera papposa, Eupatorium pur pit renin, E. 

 ageratoides, Galium aparine, Grindelia squarrosa, Hel'uvn- 

 thus annuus, H. decapeialus, H. tuber osus, Hcliopsis 

 scabra, Helenium autuuinalc, Hydro phyllum virginicum, 

 Iva xanthifolia, Lappula virginiana. Pa paver rhoeas, 

 Parietaria pennsylvanica. Phlox paniculata, Plantago 

 major, P. rugelli, Rudbeckia laciniata, Solidago canaden- 

 sis, S. mollis, S. rigida, Tragopogon porrifolius, Verbena 

 bracteosa, V. hastata, V. stricta, V . urticifolia, Verbesina 

 alternifolia, Vernonia fasiculata, Xanthium canadense. 



Atkinson, Boelus, Callaway, Crete, Chadron, Elmwood, Florence, 

 Fremont, Greeley, Hastings, Harrison, Lincoln, Long Pine, 

 Loup City, Naponee, Riverton, Saltillo, Wabash, Weeping 

 Water, Wood River, Warbonnet Canyon, Valentine, Red 

 Cloud, Bloomington, St. Paul, Simeon, Burwell, Ainsworth, 

 Calloway. 



Erysiphe polygoni DC. 

 Erysiphe communis (Wallr.) Fr. 



Amphigenous mycelium very variable, persistent, thin, effused, 

 and arachnoid, or rarely thick, dense and lichenoid, often com- 

 pletely evanescent; perithecia gregarious to scattered, small, 65- 

 180/x, usually about 90^, cells usually distinct, 10-15^ wide; ap- 

 pendages very variable in number and length, sometimes few 

 (3-7), distinct and long, or more rarely few and short, usually 

 numerous and crowded, more or less densely interwoven, and 

 long or short, always spreading horizontally, often interwoven 

 with the mycelium, simple or branched, dark, or brown at the 

 base or throughout, or almost colorless ; asci usually few, 2-8, 

 sometimes many, usually small and ovate, but varying from ovate 

 to broadly ovate or globose, sessile or with a short pedicel, 46- 

 72 X 30-45/*; spores 3-8, 19-25 X 9~i4^- 



On: Anogra pallida, Aquilcgia vulgaris, Aster ncbraskensis, As- 

 tragalus adsurgens, A. canadensis, A. sp., Brassica napus, 

 Clematis virginiana, Falcata comosa, Lotus aincricanus, 

 Mnhlembeckia platyelados, Oenothera laciniata, Onagra 

 biennis, Pisum sativum, Polygonum aviculare, P. ramo- 

 sissimum, Ranunculus abortivus, R. cymbalaria, R. del- 

 phinifolius, Thalictritm purpuras c ens, Polygonum avicu- 

 lare. 



Belmont, Central City, Chadron, Crawford, Crete, Hastings, Lin- 

 coln, Orel, Port Niobrara, Red Cloud, St. Paul, Valentine, 



77 



