214 Illinois State Dthoraforij of Natural Historij. 



M. salicina, Lev. 



II., III. Amphigenous, the aredo mostly hypophyllous, and 

 the teleutoform more often epiphyllous. Uredosori small, cir- 

 cular, often thickly spread over the leaf surface, surrounded by 

 a thick row of paraphyses, which are strongly enlarged and 

 rounded above; uredospores subglobose or elliptical, finely 

 echinulate, 12-15 by 14-18 (*■; teleutosori various in size, usu- 

 ally flat, irregular, often thickly associated or confluent, crust- 

 like, becoming reddish brown or dark brown ; teleutospores ob- 

 long, in transverse section polygonal, about 10 by 30-37 /t4. 



On \ea.yes oi Salix rordafa : McHenry, Aug. 23, 1242,11,, 

 Aug. 24, 1276 and 1271. S. hmgifolia: McHenry, Aug. 24, 

 1254, II., Aug. 31, 1396, IT.. TIL: Lake, Aug. 27, 1350, II., TIL: 

 Lee, Sept. 11, 57S0, TL; LaSalle, Sept. 14, 2500, IL, III.; Henry, 

 Sept. 28, 1707, IT. Salix sps.: McLean, July 18, 2498, II., 

 July 20, 2497, IL, Aug. 4, 2499. IT.; Piatt. Aug. 17, 1096, TL; 

 McHenry, Aug. 24, 1278, IL, 1288, TL; Lake, Aug. 27, 1351, IL, 

 TIL; Kane. Aug. 30, 1375, IL, III,; LaSalle, Sept. 20, 1599, 

 TL, TIL: Rock Island, Sept. 21, 16L8. TL; Jersey, Oct. 14, 6315, 

 TL, TIL: Union, Oct. 24, 1977, IL: Pulaski, Nov. 4, 2228, IL, 

 ITL 



Thiimen thinks what is included in the above should be 

 separated into the following species, for which he has given 

 descriptions: M. Biglowii, M. capyeanuni^ M. Harfigii, M. 

 medusa'^ M. vitcllince, (Hedwigia XVIII. [1879] p. 77, and Bul- 

 letin Torrey Botanical Club, VI. p. 216). 



M. populina, Lev. 



IL, LIT. Amphigenous. LTredosori small, scattered over 

 the surfaces of the leaves, usually more numerous below, 

 circular, surrounded by a dense row of paraphyses, which are 

 clavate or strongly enlarged and rounded above, powdery, 

 orange-yellow; uredospores varying from subglobose to oblong 

 or clavate, echinulate, 13-20 by 21-80 ^; teleutosori scattered, 

 mostly thickly studding both surfaces of the leaf, flat, compact, 

 crust-like, often confluent, reddish brown; teleutospores oblong, 

 prismatic, epispore thin, smooth, one-celled, 15 by 36-45 ^. 



On leaves of Poptdas tremuloides: McHenry, Aug. 20, 

 1196. F. monilifem: Tazewell, July 22, 2509, IL; McLean, 



