154 Bulletin 313 



UsTiLAGO PUSTULATA T. & E. — On the inflorescence of Panicum 

 proliferiim. "Sori usually in ovaries, sometimes also in stamens, 

 forming ovate bodies about 2-4 mm. in length, occasionally in stems 

 near nodes or at base of inflorescence and then forming more con- 

 spicuous often nodular swellings one to several centimeters in length, 

 with dehiscence of the thin smooth membrane disclosing a dusty 

 olive-brown spore-mass ; spores chiefly ovoid to spherical, occasion- 

 ally more irregular, usually prominently echinulate, 9-12 fx, the most 

 elongate rarelv \S ix,\n length." North American Flora, v. 7, p. 14 

 (1906). 



S8S. Infected inflorescence of P. proliferiim. 889. Spores, 1/12. 



UsTiLAGO RABENHORSTiANA Kiihn. — On the inflorescence of crab- 

 grass. "Sori usually involving the entire inflorescence, linear-oblong, 

 3-5 cm. in length, at first hidden by the enveloping leaf-sheaths but 

 finally more or less visible as a black-brown dusty mass of spores sur- 

 rounding the elongate remnants of the inflorescence ; spores reddish 

 olive-brown, ovoid to spherical or occasionally somewhat angled, 

 echinulate or verruculose, usually 10-14 fx in length." North Ameri- 

 can Flora, V. 7, p. 17 (1906). 



890. Infected inflorescence of "crab-grass. 891. Spores, 1/12. 



UsTiLAGO STRi^FORMis (West.) Niessl. — On redtop grass. "Sori 

 in leaves rarely in the inflorescence, from short linear often extend- 

 ing apparently by terminal fusion for several cm., also occasionally 

 fusing laterally to cover most of the leaf, at first covered by epider- 

 mis but this soon ruptured and dusty broAvn-black lines of spores be- 

 coming scattered and leaves shredded, spores usually ellipsoidal to 

 spherical, occasionally irregular, prominently echinulate, chiefly 

 9-14 /x in length." North American Flora, v. 7, p. 18 (1906). 



892. Spores, 1/12. 



UsTiLAGO TRiTici (Pers.) Rostr. — On inflorescence of wheat. 

 "Sori in spikelets, forming a dusty olive-brown spore-mass, about 

 3-12 mm. long by half as wide, usually entirely destroying floral 

 parts and eventually becoming dissipated and leaving behind only the 

 naked rachis ; spores lighter-colored on one side, usually subspheri- 

 cal, occasionally more elongate, minutely echinulate especially on the 

 lighter side 5-9 /a in length." North American Flora, v. 7, p. 8 

 (1906). 



893. Infected heads of wheat. 894. Spores, 1/12. 



