Parasitic Fungi of Illinois. 197 



Hypogenous; spots pallid or none ; sori oblong or linear, sometimes 

 regularly arranged at equal intervals in long parallel lines, narrow, sur- 

 rounded by the ruptured epidermis, black ; spores narrow, oblong-cla- 

 vate or elongated, septate above the middle, strongly constricted, having 

 the lower cell more narrow than the upper, and cylindrical or slightly 

 tapering downwards, .0018-. 0024 in. long, '0006 in. broad ; peduncle 

 colored, thick, very short. Peck, XXV. Rep. N. Y. Mus., p. 123. 



On leaves of Scirpus atrovirens: Piatt, Aug. 16, 1093; 

 Cook, Sept. 5, 1451. 



P. windsoriae, Schw. 



II. ; III. Hypogenous, occasionally somewhat amphige- 

 nous. Sori small, little elevated, irregularly scattered, very 

 numerous, sparingly confluent, linear or oblong, soon naked, 

 the ruptured epidermis scarcely evident; uredospores subglo- 

 bose or obovate, epispore medium thick, sharply echinulate, 

 rather deep brown, 18-24 t*-', teleutospores broadly elliptical or 

 obovate, slightly or not at all constricted at the septum, mostly 

 obtusely rounded at the ends, upper segment mostly larger, 

 vertex slightly thickened, smooth, 18-21 by 27-39 ^; pedicel 

 about the length of the spore or shorter, stout, rather deeply 

 colored. 



On Muhlenbergia: Stephenson, Sept. 13, 5834, II, III. 



P. graminis, Pers. 



I. Hypogenous. Spots definite, usually small, purple, 

 somewhat thickened; aecidia irregularly crowded, or sometimes 

 circinate, short, border narrow, numerously lacerated, little re- 

 curved; spores subglobose or angular, epispore thin, minutely 

 tuberculate, contents fine-granular, 11-15 ^; spermagonia mi- 

 nute, clustered, not usually numerous, opposite the aecidia. 



II. Amphigenous. Sori linear, on the leaves short and 

 scattered, on the leaf-sheaths often confluent in long lines, 

 orange-yellow; spores narrowly obovate or elliptical, epispore 

 thick, strongly echinulate, 18-21 by 27-36 /*. 



III. Sori linear to elliptical, often confluent in long lines, 

 mostly on the leaf -sheaths, rather prominent, soon naked, black; 

 spores clavate or narrowly elliptical, mostly somewhat con- 

 stricted, vertex strongly thickened, often pointed but some- 



