NATIVE GRASSES AND PUCCINIA GRAMINIS 167 



"P. phlei-pratcnsis is not the only rust found upon timothy ; during 

 the summer of 1910 a rust was found (by Miss King) upon the 

 leaves of timothy which was growing adjacent to wild rye (Elymus 

 robitstus) which was abundantly affected by Puccinia impaticntis, 

 and which this rust closely i:esembled. 



"Several interesting papers have been published on timothy rust. 

 Ericksson and Henning' regarded this rust as a distinct species. A 

 similar view is expressed by E. C. Johnson*. The writer and Miss 

 King in the quotation above regard it as a form of P. graminis and 

 this was likewise done by Torrey'\ 



Stakman and Louise Jensen*' state that the rust of timothy w^as 

 transferred directly from timothy to Arena sativa, Hordeum vulgare, 

 Secale cereale, Avena fatiia, Arrenathcrum clathis, Dactylis glomer- 

 ata, Elymus virginiciis, Lolium itaUcum, Lolium percnnc and Bro- 

 mus tectorum. The statement of E. C. Johnson is that, using Avena 

 sativa as a bridging host, the timothy rust could be transferred to 

 common barley. Stakman and Jensen found that wheat could not be 

 infected without a bridging host. 



E. C. Stakman and F. J. PiemeiseF, in a paper on infection of tim- 

 othy by Puccinia graminis, state that the ability of timothy rust to 

 infect the barberry is still a matter of doubt. They say : "From its 

 close similarity to P. graminis avencc, however, it seems reasonable 

 to suppose that it may possibly have developed from some form of 

 P. graminis. Since P. phlei-pratensis resembles P. graminis avenac 

 parasitically more closely than any other biologic form of P. 

 graminis it would seem that infection of timothy with P. graminis 

 avenae might be possible." "Until further, more extensive attempts 

 are made to infect barberries with teliospores of P. phlei-pratensis 

 and until the possibilities of developing experimentally a strain of P. 

 graminis on timothy have been exhausted, work is more desirable 

 than words, but the fact that P. phlei-pratensis can infect three of 

 the cereals and a number of grasses and that timothy can be infected 

 by P. graminis avena: may possibly indicate that timothy rust, as 

 Kern has previously suggested, may not be so far removed from P. 

 graminis as has sometimes been supposed." 



In a later paper Stakman and F. J. PiemeiseP find that there is 

 very little if any difference between strains. "The rust failed to in- 



*Die Hauptresultate einer neuen untersuchung uber die Getreide roste : Zeitsch 



Pflanzenk ^: 66-73, 140-142, 197-202, 257-262. 



♦Timothy rust in the United States. Bull Bur. PI. Ind. U. S. Dept. Agr. 224. 



'Torreya 9 : 1-5. 



•Jour. Agrl. Research 5:211-216. 



'Jour. Ag-rl. Research 6: 813-816. 



•Jour. Agrl. Research 10: 458. 



