178 Illinois State Laboratory of Natural Histonj. 



The uredoform is Uromyces prunorum, Fckl. The shape 

 and attachment of the cells of the teleutospores vary on differ- 

 ent hosts. On Prunus Americana the cells are nearly or quite 

 globular, and easily separated, while on P. serotina they are 

 well joined and variable. 



Nees (Syst. d. Pilze u. Schwamme [1816]). under the 

 generic name of Dicoeoma, separated the Puccinia species in 

 which the spores spontaneously divided at the septum before 

 germination. P. pruni-spinosce belongs to this group. 



P. Peckiana, Howe. 



III. Hypogenous. Sori small, scattered, few or many, 

 sometimes sparingly confluent, cinnamon-brown, powdery; 

 spores in one view more or less triangular, in the other, at right 

 angles to the first, elliptical, not constricted at segment, upper 

 segment triangular, with a small hyaline, obtusely rounded 

 apiculus, lower segment in side view somewhat quadrate, with 

 two basal projections, to one of which the pedicel is attached, 

 and the other is terminated with a hyaline apiculus similar to 

 that of the upper segment, 22-27 (base) by 36-45 /u; pedicel 

 hyaline, fragile. 



On Rubus villosm: Urbana, July 24, 1884, T. J. Burrill. 



This may be the teleutoform of what is called Cceoma 

 nitens, Schw., the u orange rust" of the blackberry, so well 

 known to horticulturists. The Puccinia has also been found 

 on raspberry leaves in New York, and the Cceoma sometimes 

 occurs on the latter host. Puccinia tripustulata, Peck, is 

 the same species, and so admitted by the author of the latter 

 name. 



P. tiarellse, B. & C. 



III. Amphigenous. Spots small, distinct, reddish brown; 

 sori scattered, circular, prominent, on the petioles more or less 

 elongated and sometimes confluent, chestnut-brown; spores 

 elliptical, constricted at the septum, vertex much thickened, 

 and usually prominently pointed, base mostly obtusely rounded, 

 epispore rather thin, smooth, 12-18 by 21-36 /*; pedicel nearly 

 hyaline, very slender, once to twice as long as the spore. 



OnMitella diphyUa: Kane. Aug. 30, 1382. 



