238 NORTH AMERICAN FLORA [Volume 7 



33. Nigredo Pontederiae (W. Gerard) Arthur. 



Uromyces Pontederiae W. Gerard, Bull. Torrey Club 6: 31. 1875. 

 Uredo Pontederiae Speg. Anal. Soc. Ci. Argent. 9: 172. 1880. 

 Uromyces Pontederiae Speg. Anal. Soc. Ci. Argent. 26 : 12. 1888. 



O and I. Pycnia and aecia unknown. ' 



II. Uredinia amphigenous, scattered, on small purplish spots, small, roundish or oval, 

 0.3-0.5 mm. across, rather tardily naked, light cinnamon-brown, somewhat pulverulent, 

 ruptured epidermis noticeable ; urediniospores ellipsoid, 18-21 by 23-29 \i\ wall golden- 

 brown, rather thin, l-1.5ju, moderately and sharply echinulate, the pores 4, equatorial, 

 rather obscure. 



III. Telia amphigenous, scattered or sometimes in small groups, often on small 

 purplish spots, roundish or oval, 0.2-0.4 mm. across, tardily naked, pulvinate, chocolate- 

 brown, ruptured epidermis conspicuous ; teliospores obovoid or broadly clavate, 13-18 by 

 21-29 /i, rounded or obtuse above, usuall5^ narrowed below; wall golden-brown, rather thin, 

 1-1. 5 /J, much thicker above, 5-9 /x, smooth; pedicel tinted, short, length of spore or less. 



On Pontederiaceae : 



Pontederia cordata Iv., Delaware, Florida, Georgia, Missouri, New York. 

 Type locality: Poughkeepsie, New York, on Pontederia cordata. 



Distribution: Along the Atlantic coast from southeastern New York southward, and in 

 Missouri ; also in South America. 

 ExsiCCATi : Rav. Fungi Am. 793. 



34. Nigredo Juaci (Desmaz.) Arthur. 



Pucciniajunci Desmaz. PI. Crypt. 81. 1825. 



Aecidium zonale Duby, Bot. Gall. 2 : 906. 1830. 



Uromyces Junci L. Tul. Ann. Sci. Nat. IV. 2 : 146. 1854. 



Puccinella iruncaia Fuckel, Enum. Fung. 18. 1861. 



Puccinella Junci Fuckel, Symb. Myc. 60. 1869. 



Caeomurus Junci Kuntze, Rev. Gen. 3^ : 450. 1898. 



Aecidium Cardui Arth. Bull. Torrey Club 33 : ?>?>. 1906. Not A . Cardui Sydow. 1901. 



0. Pycnia epiphyllous, in small groups, inconspicuous, immersed, orange-yellow, 

 globose, 130-180 ju in diameter. 



1. Aecia hypophyllous, crowded in circinating groups 3-5 mm. across, on discolored 

 spots, rather short, cupulate, 0.2-0.3 mm. in diameter ; peridium colorless, the margin erect 

 or spreading, erose ; peridial cells rhombic, 26-35 ^ long, overlapping, the walls transversely 

 striate, the outer wall about 7-9 /i thick, the inner wall somewhat thinner, 3-5 /i ; aeciospores 

 globoid, small, 15-18 by 16-20 ju; wall nearly colorless, very thin, 1-1.5 jLt, very minutely 

 verruculose. 



On Ambrosiaceae : 



Ambrosia p silo stachy a DC, Colorado, Nebraska, North Dakota. 

 On Carduaceae : 



Arnica celsa A. Nels., Colorado. 



Arnica cordifolia Hook., South Dakota. 



Cirsium Flodmanii (Rydb.) Arth. {Cardzius J*'lodfnanii 'Rydb.), North Dakota. 



Cirsium. Hookerianum Nutt. {Carduus Hookerianus Hellei), Montana. 



II. Uredinia amphigenous, numerous, scattered, roundish or elongate, 0.3-0.5 mm. 

 broad by 0.3-1.5 mm. long, at first covered by the epidermis, finally naked, dark cinnamon- 

 brown, ruptured epidermis very conspicuous ; urediniospores broadly ellipsoid or occasion- 

 ally slightly obovoid, 16-21 by 18-28 jn; wall pale cinnamon-brown, about 1.5-2 ju thick, 

 sparsely and rather prominently verrucose with widely separated blunt papillae, the pores 

 2, rarely 3, equatorial. 



III. Telia amphigenous, numerous, scattered, roundish, irregular, or often elongate, 

 0.2-0.8 mm. wide by 0.5-2 mm. or more long, often confluent, soon naked, firm, blackish- 

 brown, ruptured epidermis conspicuous; teliospores angularly obovoid, rounded or acu- 

 minate above, usually narrowed below, 15-21 by 26-40 ju ; wall chestnut-brown, 1.5-2 ju thick, 

 much thicker at apex, 7-13 /x, smooth; pedicel tinted, once to twice length of spore. 



The spegies appears to have well marked races with aecia on different genera of the Carduaceae 

 and Ambrosiaceae. In America only aecia on Cirsium. have been proved by cultures to-belongto 

 it, while in Europe the best known form goes to Pulicaria. 



