308 Illinois State Laboratory of Natural History. 



Note. Three other genera have been described as follows : 



(1). Pleochseta (Saccardo, Sylloge Fungorum, I., p. 9). Perithecia 

 globose-lenticular, indehiscent, texture subcoriaceous, parenchymatous ; 

 appendages very numerous, rod-like, straight, simple, hyaline ; asci 

 clavate, two-spored; spores simple, elliptical, subhyaline. P. Curtisii, 

 Sacc. & Speg. occurs on leaves of Cellis in Alabama and Carolina, and in 

 South America. 



(2). Erysiphella (Peck, 28th Report, New York State Museum p. 63). 

 " Perithecia destitute of appendages, spores definite." E. aggregata, Peck, 

 is described on the fertile aments of Alnus serrulata. 



(3). Saccardia (Cooke, Grevillea VII. [1878], p. 49). Mycelium 

 arachnoid, often evanescent ; perithecia globose, asci globose-ovate, 

 8-spored; spores elliptical, many-celled ; appendages none or interwoven 

 with the mycelium. S. quercina, Cooke on the leaves of Quercus virens, 

 Georgia, and S. Martii, Ell. & Sacc. on Q. laurifoKa, Florida, have been 

 described. None of these plants are known in Illinois. Doubts may be 

 expressed as to the validity of these groups as genera ef ErysiphesR. 



Calodadia, Le"v. is a synonym for Microsphsera, but was previously 

 used for a genus of Algse. 



Erysibe was used for Erysiphe by several authors, and TVallroth's 

 genus Alphitomorpha was made to include all of the Erysiphese. 



SPHJEROTHECA, Lev. 



(Ann. Sci. Nat., Series III., Tome XV., p. 138.) 



Perithecium containing only one ascus. Appendages simple 

 threads not unlike the mycelium with which they are 

 frequently interwoven. Ascus suborbicular, usually con- 

 taining eight spores. Very rarely two asci have been observed. 



S. pannosa, ( Wallr. ) Lev. 

 (1. c. p. 138.) 



Alphitomorpha pannosa, Wallr. (Verhand. d. Naturf. Freunde, I., p. 43). 

 Erysibe pannosa, Lk. (Species Plant. VI., I., p. 104). 

 Eurotium rosarum, Grev. (Scott. Crypt. Fl. III., p. 164, Fig. 2). 



Mycelium abundant on the leaves, stems, etc., often sterile; 

 perithecia more often occurring on the branches, scattered, 

 delicate, 90-100 /&, reticulations evident, small, 10-15 ^\ ap- 

 pendages short and delicate, much interwoven with the 

 mycelium, sometimes colored ; ascus large, delicate, ovate, 

 expanding, when free from the perithecium, to a length greater 

 than its diameter; spores 8, large, 29 ^ long. 



