Parasitic Fuufji of Illinois. 409 



ous, slender, simple, about equal to the diameter of the perithe- 

 cium, hyaline, smooth, tips not swollen, ascending from the 

 upper half of the perithecium; asci numerous, 14 or more, long 

 and slender, oblong or narrowly ovate, pedicellate, about 30 by 

 75 ft; spores 8, small, about 10 by 15 /*. 



Mycelium dense, effuse, persistent; conceptacles large, depressed 

 or flattened, black; appendages very numerous, slender, about equal in 

 length to the diameter of the conceptacle, simple, colorless; sporangia 

 oblong or narrowly ovate, eight to sixteen, containing eight spores.— 

 Peck, 25th Rep. N. Y. State Mus. p. 26. 



On Acer saccharinum: Champaign, Oct. 17 (Waite). 



This is distinguished from U. aceris, (DC.) Lev. by its 

 sin) pie appendages, and more numerous, very narrow asci. In 

 our specimens the mycelium is quite inconspicuous, but in 

 specimens from Massachusetts (Seymour) it is more abundant. 

 The leaves affected by it can be distinguished at some distance, 

 as the areas covered by it remain green after the rest of the 

 leaf has assumed its autumn tint. (Waite.) 



U. parvula, C. & P. 



(Erysiphei of the U. S. in Jour, of Bot. 1872.) 



Amphigenous. Perithecia small, 90-100 ^, delicate, retic- 

 ulations distinct, small and regular, averaging about 10 /it; 

 appendages very numerous, delicate, slender, hyaline, shorter 

 than the diameter of the perithecium; asci 5-7, broadly elliptic; 

 spores 6-8, mostly 6, large, 20-25 jtt long. 



Hypophyllous; mycelium effused, delicate, evanescent ; perithecia 

 scattered, globose, minute; appendages simple, numerous, scarcely so 

 long as the diameter of the perithecia ; asci elliptical, rostrate ; spores 

 6. — Cooke and Peck, Erysiphei of the U. S., Supp. in Jour, of Bot., 

 June, 1872. 



On Celtis occidentalis: Union, Oct. 26, 2036; Oct. 31, 2144; 

 Jackson, Nov. 5, 2264. 



This is perhaps too near U. Sal ids, (DC.) Winter, but it 

 seems to be distinguished by its uniformly smaller size and its 

 shorter, more delicate appendages. 



