PROTOBASIDIOMYCETES 



397 



advances. These spores arc 20-35 x I 5- 22 / x , and a spore ger- 

 minates by the production of the characteristic promycelium, di- 

 vided ordinarily into four cells, each producing its sporidium. The 

 germination of the teleutospore would seem to take place ordinarily 

 several weeks prior to the appearance of the spermogonium and 

 aecidium, both of which arise only from teleutosporic infection. 

 Sydow accepts the separation of the rust of clovers into two spe- 

 cies. The absence of stages O, I, also the more numerous germ- 

 pores in II, distinguish the form on red clover from that on white. 



FKI. 196. UROMYCES* APPENDtcvLATUs : RUST OF BKANS. (Photograph by 

 H. H. Whetzel) 



As a rule, control measures seem to be unnecessary ; at any rate 

 no practical preventive methods are known. 



V. RUST OF BEANS 

 f^t'flmyct's appcndiculatus (Ters.) Lev. 



DE BARV. A. Rccherches sur le deVeloppement cle quelques champignons 

 parasites. Ann. d. Sci. nat. Bot. (SeY. 4) 20: 68-99. 1863. 



WHETZEL, H. H. Bean Rust. Cornell Agl. Exp. Sta. Built. 239 : 298-299. 

 figs. 113-113. 1906. 



This fungus is widely distributed, occurring on the bean (Phaseo- 

 lus vulgaris) and other related species. It is also reported in south- 

 ern latitudes on relatives of the cowpea, such as Dolichos ornatus, 



