186 Illinois State Laboratory of Natural History. 



Var. VernonisB. 



Amphigenous; spots small, purple, with a pule yellow bor- 

 der, or yellow only, sometimes indistinct: sori scattered, sub- 

 rotund, prominent, blackish brown or black; spores oblong- 

 elliptical, mostly regularly rounded at the ends, slightly con- 

 stricted, a central nucleus in each cell, 20 by 42 ^; pedicel 

 hyaline, about four times as long as the spore. Uredospores 

 preceding or accompanying the teleutosp6res, not numerous, 

 subglobose, sharply echinulate, about 25 /* in diameter. 



On Vernonia fasciculata: Champaign, Aug. 11, 1014; 

 Piatt, Aug. 16, 1094, Aug. 17, 1098, 1102; McLean, Sept. 6, 

 5670, Oct. 12, 1844, 1850; LaSalle, Sept. 14, 1527, Sept. W, 

 6254; JoDaviess, Sept. 19, 5996. 



Schweinitz (N. Am. Fungi, No. 2926) calls this form P. 

 Vernonice, and describes it as follows: 



" Spots none. Differing from P. lielianthi in the rather large pulvinate 

 sori, and the delicate ferruginous color of the spores. It sometimes oc- 

 curs also on species of Helianthus." 



But the gradation of forms between this and the typical 

 P. helianthi leaves no sufficient ground for specific distinction. 

 Further, P. helianthi seems to be P. tanaceti, DC. Winter 

 (Rtibh. Krypt., Fl. I., p. 209) unites the two, while Schroter 

 (Hedw. XIV., p. 180) maintains that they are distinct, basing 

 his arguments on distribution. The size, shape, and color of the 

 spores vary greatly, but are so connected by intermediate forms 

 that no specific distinction can be founded on these character- 

 istics. Cultures are necessary to determine such distinction if 

 there is any. In the meantime, so long as we are unable to 

 recognize a difference by appearance, there can be no question 

 as to which name to choose, even though this carries us against 

 common usage and our own habit. 



P. flosculosorum, (Alb. & Schw.) Itoehl. 



II., III. Amphigenous. Sori small, scattered or in small 

 clusters. Uredospores subglobose, sharply echinulate, mostly 

 rather thick walled, 24-;$0 ^; .teleutospores broadly elliptical or 

 oval, constriction little or none, rarely thickened at the apex. 



