444 



Journal of Agricultural Research 



Vol. X, No. 9 



The fact is as yet unexplained. The failure of the inoculations in 1914 

 was probably due to the fact that the rust on the grass was old. 



Table XI. — Results 0/ inoculations with urediniospores from Avena fatua L. 



No. 



Place. 



Williston, N. Dak 

 Glasgow, Mont. .. , 

 Pullman, Wash. .. 



1916. 

 Sept. 18 



Sept. 22 



Sept. 30 



Secede 

 cereals. 



3_ 

 19 



Avena fatua can be as easily infected with P. graminis avenae as A. 

 sativa itself, and is often infected with the stemrust of oats in the field 

 (Table XI). The writers have observed it very often in different locali- 

 ties. Apparently the rust developed on wheat was P. graminis tritici. 

 Successful infection can be very easily explained by the fact that the 

 Avena fatxia plants from which inoculations were made were growing 

 with Agropyron tenerum and A. smithii, both of which were badly affected 

 with P. graminis tritici. The A. fatua plants might easily have touched 

 the Agropyrons, thus becoming contaminated with P. graminis tritici. 

 The rust developed on barley and rye was undoubtedly P. graminis 

 avenae, since it easily transferred to oats. 



A. fatua is also a congenial host for the crownrust of oats. The grass 

 was found quite often heavily rusted. 



Table XII. — Results of inoculations ivith urediniospores from Dactylis glomerata L. 



