410 Illinois State Laboratory of Natural History. 



U. salicis, (DC.) Winter. 

 (Die Pilze, II., p. 40.) 



Erysiphe salicis, DC. (Flore Franc, II., p. 278). 



Erysiphe populi, DC. (Flore Franc, VI., p. 104). 



Alphifomorpha adunca, guttata, Wallr. (Verh. Naturf. Freunde, I., pp. 



37, 42). 

 Erysibe adunca, obtusata, Lk. (Spec. Plant., VI., 1, p. 117). 

 Erysiphe adunca, Grev. (Scott. Crypt. Flora, V., tab. 296). 



Uncinula adunca, Ldv. (Ann. Sci. Nat., Ser. III., Tome XV). 



Uncinula leuculenta, Howe (Trans. Albany Inst., VII., quoted in 

 Amer. Nat., VII., p. 58). 



Uncinula heliciformis, Howe (Torr. Bull., V., p. 4). 



Amphigenous. Mycelium abundant, persistent; perithecia 

 usually large, 100-160 fi, wall-tissue soft, elastic, reticulations 

 rather small and indistinct; appendages variable in number, 

 usually very numerous, hyaline, not much svrollen at the tip, 

 once to tv\rice as long as the diameter of the perithecium; asci 

 from 4 or 5 to 12 or more, ovate; spores usually 4 or 5, some- 

 times 6-8. 



On Salix sps.: La Salle, Sept. 20, 1602; Henry, Sept. 28, 

 1721; Jo Daviess, Sept. 20, 6029, 6030, 6031; Stephenson, Sept. 

 21, 6083. Salix petiolaris: Piatt, Aug. 17, 1143. Salix cor- 

 data: McHenry, Aug. 20, 1152, Aug. 24, 1255, 1256; Cook, Sept. 

 5, 1435; Jo Daviess, Sept. 18, 5974. Populus tremuloides: 

 McHenry, Aug. 23, 1250, Aug. 31, 1397; Jo Daviess, Sept. 

 18, 6018. Popuhis grandidentata : La Salle, Sept. 17, 1579, 

 Populus heterophylla: Union, Oct. 25, 2020, 2031; Oct. 31, 

 2142. 



This species is quite variable, as are most of the abundant 

 and widely distributed ones belonging to the family. It is 

 usually known as U. adunca, Lev. ; but De Candolle's name has 

 priority, and is adopted by Winter (Die Pilze, II., p. 40) and 

 Tulasne (Fung. Carp, I., p, 198), The asci are usually described 

 with only four or five spores, but our specimens frequently show 

 as many as six, and sometimes seven or eight. 



U. leucidenta, Howe, is described as occurring on Populus, 

 with fewer and longer appendages and five or six spores. Illi- 

 nois specimens on Populus sometimes show rather longer ap- 

 pendages than on Salix, but as the more numerous spores are 

 frequent on both hosts, there is i^o sufficient ground for sepa- 



