Parasitic Fungi of Illinois. 231 



On Eupatorium. Hypophyllous. Spots distinct, usually 

 few, conspicuous, yellow; aecidia irregularly clustered or some- 

 what circinate, short, irregularly split and moderately recurved, 

 soonjpulverulent; spores subglobose, epispore rather thin, mi- 

 nutely tuberculate, 18-20 ^- spermagonia several, scattered, 

 above, honey-yellow. On Eupatorinm perfoliatum: McLean, 

 July 11, 2424 



On Silphium: Hypophyllous, and often also epiphyllous. 

 Spots distinct, usually widely scattered, not large, yellow, 

 aecidia irregularly" associated, scarcely crowded, deeply im- 

 mersed, and but slightly projecting above the raised epidermal 

 border, margin many times split or pulverulent, little excurved; 

 spores subglobose, often angular, 11-15 ^; spermagonia rather 

 few, conspicuous, reddish brown, central, on both sides of leaf. 

 On Si(/)/rii(nt integrifolium : McLean, May 3, 4852. S. terebin- 

 thhiaceum: McLean,|May 30,4825, June 23, 5274, July 2, 2420, 

 July^ll, 2421. S. laciniatum: McLean, June, coll. C. A. Hart. 



On Ambrosia: Hypophyllous. Spots large, often conflu- 

 ent, scarcely^thickened, yellow or purplish brown; aecidia not 

 closely ^crowded, irregularly distributed over the spot, with, 

 however, a free central area, short, but not deeply immersed, 

 firm, the coarsely divided border widely and elegantly excurved ; 

 spores subglobose, usually angular, epispore firm, smooth, 12- 

 15 /*; spermagonia few, central, on both leaf -surf aces, reddish 

 orown. On Ambrosia trifida: Champaign, June. 



On Xanthium : Hypophyllous, very rarely also epiphyllous. 

 Spots not large, distant, scarcely thickened, yellowish, some- 

 times tinged purple; aecidia not densely crowded, irregularly 

 distributed or subcircinate, mostly irregular in outline, deeply 

 immersed and protruding little above the raised epidermal bor- 

 der, the margin pulverulent, rarely lobed and excurved; spores 

 subglobose or elliptical, often angular, epispore rather thin, 

 minutely tuberculate, about 15-18 ,t*; spermagonia few, central, 

 mostly above, minute, yellowish brown. On Xanthium stru- 

 marium: Champaign, June. This is much like the form on 

 Silpliium, and answers in some respects to JE.'verbesince, Schw., 

 and also to jE. tracheliifoliatum, Schw., but it is probably 

 neither. The JEcidium is often followed by Puccinia xanthii, 

 Schw., and may be connected therewith. 

 17 



