The Erysiphaceae of Nebraska 13 



Crete, Florence, Lincoln, Saltillo, Weeping Water. 



Uncinula macrospora Peck 

 Uncinula intermedia B. & C. 



Amphigenous ; mycelium evanescent or sub-persistent, and 

 pruinose, sometimes forming circumscribed patcbes on the upper 

 surface of the leaf ; perithecia closely gregarious in small patches, 

 or scattered over the surface, globose-depressed or lenticular, 

 95-165/A in diameter, averaging 130/x, cells about io/x, wide; ap- 

 pendages numerous, 50—130 or more, varying in length from one- 

 third the diameter of the perithecium to a little more than its 

 diameter, smooth, colorless, aseptate, simple, thick-walled at the 

 base, tip usually simply uncinate ; asci 8-20, sub-pryif orm or el- 

 liptic oblong, often curved, 54-65 X29-35/X,; spores 2, 30 X 15- 



On : Ulmus amcricana. 

 Crete, Elmwood, Grand Island, Lincoln, Nehawka, Plattsmouth, 

 Roca, Saltillo, Union, Wabash, Weeping Water. 



Uncinula salicis (DC.) Winter 



Erysiphe salicis DC. 

 Uncinula adunca Lev. 



Amphigenous ; mycelium evanescent, or persistent in thin ef- 

 fused areas or sometimes densely compacted in definite circum- 

 scribed patches ; perithecia gregarious, or more or less scattered, 

 globose-depressed or lenticular, 90 X l 7S^ m diameter, averaging 

 135/u., cells 10-15/i, wide; appendages numerous, often densely 

 crowded, 100-150 or more, three-fourths to one and one-half 

 times the diameter of the perithecium, simple, aseptate, or oc- 

 casionally i-septate at the base, hyaline and thin-walled through- 

 out, tip simply uncinate ; asci 8-14, rarely only 4-6, elliptic-oblong 

 or broadly ovate, usually pedicellate, 50-80 X 30-40^, averaging 

 68 X 36//.; spores 4-6, 20-26 X 10-15^. 



On: Salix amygdaloides, S. cor data, S. fluviatalis, S. lutnudis, 

 S. nigra, S. sp., Populus deltoidcs 

 Ashland, Crete, Lincoln, Long Pine, Milford, Valentine, Wabash, 

 Weeping Water. 



Uncinula circinata Cook & Peck 



Hypophyllous or sometimes with us amphigenous ; mycelium 

 evanescent or sub-persistent on the upper surface of the leaf, 

 sometimes forming definite spots ; perithecia usually scattered, 



71 



