The Erysiphaceae of Nebraska 1 5 



dose, colorless aseptate, tip 3-4 times dichotomously branched, 

 branching very irregular and lax, branches strongly flexuose, of- 

 ten more or less curled, tips of ultimate branches straight or 

 curved; asci 4-13, rarely more, ovate or ovate-oblong, with a 

 short pedicel, 48-66 X 2 6~35/* ', spores usually 4, sometimes only 

 3, or sometimes 5-64, 19-21 X 10-12/*. 



On : Euphorbia marginata. 

 Cass County, Red Cloud, Riverton. 



Microsphaera alui (Wallr.) Winter. 



Alphitromorpha alni Wallr. 



Microsphaera quercina (Schwein.) (Burrill) (partim). 



Amphigenous ; mycelium evanescent or persistent in thin, more 

 or less effused areas over the surface of the leaf ; perithecia 

 scattered or more or less densely gregarious, globose-depressed, 

 very variable in size, usually small, 66-1 10/* in diameter, some- 

 times 1 10-135/*, cells 10-15/* wide; appendages very variable in 

 number and length, 4-26, % to 2^ times the diameter of the per- 

 ithecium, colorless throughout or more or less amber colored at 

 the base, aseptate or sometimes 1-2-septate toward the base, tip 

 more or less closely 3-6 times dichotomously branched, tips of 

 the ultimate branches regularly and distinctly recurved ; asci 3-8, 

 ovate to ovate-oblong, or globose, 42-70 X 3 2 ~5°l x , usually pedi- 

 cellate; spores 4-8, 18-23 X 10-12/*. 



On: Lathyrus odoratus, Lonicera gloucescens, Qucrcus macro- 

 carpa, Q. rubra, Syringa vulgaris, S. chincnsis. 

 Ashland, Florence, Long Pine, Loup City, Lincoln, Wabash, 

 Weeping Water, St. Paul, Riverton. 



Microsphaera alni var. vaccinii (Schwein.) Salmon. 



Microsphaera elevata Burrill. 

 Erysiphe vaccinii Schwein. 



Generally epiphyllous ; mycelium persistent or sometimes evan- 

 escent ; perithecia globose or globose-depressed, very variable in 

 size, 70-145/* in diameter, cells 10-20/* wide; appendages 4-22, 2.\ 

 times the diameter of the perithecium, delicate and thin, hyaline or 

 occasionally amber-brown at the base, 2-4 times dichotomously 

 branched, branching variable, irregular, sometimes close and 

 compact, sometimes loose and widely forked, ultimate branches 

 recurved; asci 2-16, 45-72X28-38/*; spores 4-6, 18-22 X 

 10-13/*. 



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