816 Journal of Agricultural Research vol. vi. No. 21 



capable of infecting two others, barley and rye, it is also capable of infect- 

 ing many wild grasses in this country and Europe. Until further, more 

 extensive attempts are made to infect barberries with teliospores of P. 

 phleipratensis 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. phleipratensis can infect three 

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

 by P. graminis avenae may possibly indicate that timothy rust, as Kern 

 (4, 5) has previously suggested, may not be so far removed from P. 

 graminis as has sometimes been supposed. 



SUMMARY 



(1) It has been possible by means of artificial inoculations to infect 

 various strains of timothy with Puccinia graminis avenae. 



(2) Timothy exerted an appreciable effect on the morphology of spores 

 of P. graminis avenae, reducing them considerably in size. Practically 

 identical results were obtained by transferring the rust to barley. 



(3) The rust was subnormal in vigor on timothy, the pustules always 

 remaining small. 



(4) The facts recorded in this paper are suggestive of the possible 

 origin of P. phleipratensis. 



LITERATURE CITED 



(1) Carleton, M. A. 



1899. Cereal rusts of the United States: a physiological investigation. U. S. 

 Dept. Agr. Div. Veg. Physiol, and Path. Bui. 16, 74 p., 1 fig., 4 col. pi. 

 Bibliography, p. 70-73. 



(2) Eriksson, Jakob, and Henning, Ernst. 



1894. Die Hauptresultate einer neuen Untersuchung iiber die Getreideroste. 

 In Ztschr. Pflanzenkrank., Bd. 4, p. 66-73, 140-142, 197-203, 257-262. 



(3) Johnson, E. C. 



1911. Timothy rust in the United States. U. S. Dept. Agr. Bur. Plant Indus. 

 Bui. 224, 20 p. 



(4) Kern, F. D. 



1909. The rust of timothy. In Torreya, v. 9, no. 1, p. 3-5. 



(5) 



1910. Further notes on timothy rust. In Proc. Ind. Acad. Sci., 1909, p. 417-418. 



(6) Mercer, W. H. 



1914. Investigations of timothy rust in North Dakota during 1913. In Phyto- 

 pathology, v. 4, no. 1, p. 20-22. 



(7) Stakman, E. C. 



1914. A study in cereal rusts: physiological races. Minn. Agr. Exp. Sta. Bui. 



138, 56 p., 9 pi. Bibliography, p. 50-54. 



(8) and Jensen, Louise. 



1915. Infection experiments with timothy rust. In Jour. Agr. Research, v. 5, 



no. 5, p. 2 1 1-2 16. Literature cited, p. 216. 



