212 BOTANICAL GAZETTE [march 



Literature: Burrill, Bull. 111. State Lab. Nat. Hist. 2:163. 1885; 

 Saccardo, Syll. Fung. 7:581. 1888; Arthur and Holway, Bull. Lab. Nat. 

 Hist. State Univ. Iowa 3:44. 1895; Sydow, Monog. Ured. 2:7-8. 1909. 



Uromyces Rudbeckiae has been collected more frequently than 

 any North American species of the group. Its range embodies the 

 greater part of the plains area, and extends to the Rocky Moun- 

 tains. 



Dietel (Ann. Myc. 8:305. 1910) considered Uromyces 

 Komerovii Bubak on Solidago Virgaurea identical with U. Rud- 

 beckiae. No specimens of the former have been seen, although a 

 collection on Solidago Virgaurea in the herbarium has not been 

 found to differ from U. Solidaginis. 



The only other rust found upon Rudbeckia is Aecidium Composi- 

 tor urn Auct, recently found to belong with U. perigynius Hals ted 

 (My col. 9:307), a connection suspected from the fact that the 

 telial stage of U. Rudbeckiae is similar to the telial stage of U. peri- 

 gynius. A type of correlation which has frequently been of service 

 in indicating alternate stages of heteroecious rusts is thus evidenced. 

 The cytological work upon this species is noted earlier in this 

 paper. 



11. Uromyces Bidentis Lagerh. Bull. Soc. Myc. Fr. 11:213, 



1895. — Caeomurus Bidentis Kuntze, Rev. Gen. 3 3 .'449- 1898; 





Uromyces densus Arth. Mycologia 7:196. 1915. 



O. Pycnia unknown. 



III. Telia hypophyllous, numerous, in small circinating groups 

 on roundish, discolored spots, 1-4 mm. across, sometimes confluent, 

 roundish or oval, 0.1-1 mm. across, the central sorus larger, sur- 

 rounded by smaller ones, early naked, compact, pulvinate, dull 

 cinnamon-brown, becoming waxy-cinereous from germination, 

 surrounding epidermis inconspicuous; teliospores obovoid or 

 oblong, 15-28X30-45/1, rounded or narrowed above, narrowed 

 below; wall pale golden or cinnamon-brown, thin, 1 /x, thicker 

 above, 4-9 /x, smooth; pedicel hyaline, once or twice the length 

 of the spore or less. 



Ox Carduaceae: Bidens leucantha (L) Willd., Porto Rico; B. pilosa L., 

 Porto Rico; Bidens sp., Costa Rica. 



Type locality: Ecuador, South America, on Bidens andicola. 

 Distribution: Porto Rico and Central America; also in South America. 



