456 



Journal of Agricultural Research 



Vol. X, No. 9 



barley. On this host the rust develops only weakly, while P. graminis 

 secalis develops normally. On some of the grasses susceptible to P. 

 graminis secalis, however, the Hystrix patula strain develops normally. 

 It can very easily infect and develop normally on Agropyron repens, A. 

 tenerum, A. caninum, Elymus virginicus, Hordeum jubatum, and Hystrix 

 patula. While there may be sufficient reason for considering this a 

 separate biologic form, it is probably preferable to consider it only a 

 variant form of P. graminis secalis without giving it a new name. 



Table XXIII. — Results of inoculations with urediniospores from Koeleria cristata (L.) 



Pers. 



» Grass planted in greenhouse in fall. 



6 Material badly dried. 



The rust developed in No. i (Table XXIII) was undoubtedly P. 

 graminis avenae, while that in No. 3 was very probably P. graminis 

 phleipratensis. A large number of inoculations were made on the grass 

 with the stemrust of oats, as well as with the other forms of stemrust. 

 The results showed clearly that Koeleria cristata is very susceptible to 

 P. graminis avenae, P. graminis agrostis, and P. graminis phleipratensis, 

 but not to P. graminis secalis, P. graminis tritici, or P. graminis triiici 

 compacti. 



Panicularia pauciflora was very heavily and commonly rusted in the 

 mountain valleys just west of the Continental Divide in Montana. The 

 rust proved to be ordinary P. graminis avenae (diagram 10). The char- 



DiAGRAM 10. — Results of inoculations with urediniospores from Panicularia paucijlora (Presl.) Knntze. 



P. graminis from 

 Pamcularla 

 poMCiflora — 



fWheat 



„ o 

 Rye — 



Oats 



Phleum pratense — 

 Agrostis stolonifera ~ 



Rye -3-; 2 



Barley "l^; 2 — Barley -5- 

 14 24 



Oats — — Oats — — Oats — 

 24 54 13 



t> Oats 77 



Dactylis glomerata — — Phleum pratense — — Phleum pratense v 

 7 35 «> 



Agrostis stolonifera — 



» Minute uredinia. 



Calamagrostis canadensis — 

 f> Dots indicate that a number of intervening transfers were made. 



