15 



E. graminis, DC. Flore Franc. VI, p. 106. 



Amphigenous, often epiphyllous. Mycelium dense, felt-like, per- 

 sistent, white or gray, sometimes tinted brown. Perithecia immersed 

 in the mycelium, few and scattered or many and crowded, depressed, 

 large, about 225 p (150-255 ju); appendages numerous, rather short, 

 simple or occasionally branched, rigid, but variously curved and inter- 

 woven with the mycelium, hyaline or tinted. Asci 16-25, oblong to 

 oval, pedicellate. Sporidia 8, or rarely 4, maturing late, often only on 

 old plants in the spring. 



On Beckmanma erucceformis, Panicum sanguinale, Agrostis 

 exarata, Poa tenuifolia, P. jiratensis, Glyceria nervata, G. aquatica, 

 Bromus unioloides, Hordeumjubatum, JElymus condensatus, Trit- 

 icum vulgare. 



Common, Massachusetts to California, mostly observed in the 

 conidial state (Oidium monilioides. Link) in shady places. Perithecia 

 usually forming only late in summer or autumn, and sporidia much 

 later. In Montana, however, the former have been collected in July, 

 and ripe sporidia. found in November, or even earlier (Anderson). In 

 California it has been destructive to wheat (Harkness). Anderson 

 says there are sometimes as many as 20 sporidia in an ascus, a vari- 

 ation not reported elsewhere. 



UNCINULA. Lev. 



Ann. Sci. Nat. Ser. Ill, Tome XV. 



Perithecium containing several asci. Appendages free from the 

 mycelium, recurved or coiled at the tip. 



U. Clintonii, Peck, Trans. Albany Inst. VII, p. 216, 25th Rep. 

 N. Y. State Mus. p. 106. 



Amphigenous. Mycelium thin, rather persistent. Perithecia scat- 

 tered, 90-120 ju } firm, nearly black; appendages 15-30, 1-1 J times 

 diameter of perithecium in length, hyaline or nearly so, uncinate- 

 coiled at the tip. Asci 4-6, oval, very short-beaked. Sporidia 4-8. 

 mostly 18-21 /i long, completely filling the ascus. 



On Tilia Americana, not very common. Apparently often 

 escaping observation. Reported from New York (Peck), Wisconsin 

 (Davis), Iowa (Pammel), and Illinois. 



U. necator, (Schw.) 



Erysiphe necator, Schw. Syn. N. Am. 2495. 



Uncinula spiralis, Berk. Crypt. Bot. p. 268, fig. 64. 



Uncinula Ampelopsidis, Peck, Trans. Albany Inst. VII, p. 216. 



Uncinula Americana, Howe, Erysiph. U. S. Journ. Bot. 1872, 



Uncinula subfusca, B. & C. Grev. IV, p. 160. 



Uncinula necator, Burrill (this publication). 



