Mains : Heteroecism of Puccinia 



317 



sarily mean a connection between the two forms, as the grass rust 

 may have come from aecia upon a plant which had died down and 

 disappeared earlier in the season. Mr. Bethel remarked that the 

 situation was made the more difficult to explain by the absence of 

 Kocleria cristata, the grass host supposedly connected with the 

 Berberis aecia. On this account, and because of the insistence of 

 Dr. Coons that there must be some connection between the aecia 

 upon Berberis Fcndlcri and the associated grass rust, he sent the 

 material for culture and study. An examination of the material 

 showed that the rust on Berberis Fendleri was Aecidium Fendleri 

 Tracy & Earle, and that on the grasses was Puccinia montanensis. 

 As such a connection would add an entirely new aecial host in a 

 genus rather far removed from Hydrdphyllum, it became impor- 

 tant to establish or disprove this by cultures. The aeciospores, 

 proving viable, were sown and produced infection upon Hordeum 

 jubatum and Hystrix Hystrix. In the meantime Mr. Bethel made 

 a sowing in his garden at Denver, Colo., from a part of the same 

 collection of aecia and obtained infection upon Agropyron tencrum. 

 Mr. Bethel was kind enough to send some of this material to me 

 for study. 



Further evidence of this connection was obtained from cultures 

 made in the spring of 1920. Four collections gave infection upon 

 Berberis Fendleri. Of these, three were from Mancos, Colo., on 

 Agropyron tencrum, A. Smithii and Agropyron sp., rusted grasses 

 associated with the Berberis Fendleri used in the aecial culture 

 mentioned above. The fourth culture was from telia obtained by 

 Mr. Bethel at Denver by sowing the above aecial material on 

 Agropyron tenerum. Ten other collections, eight from Colorado 

 and two from Indiana, were sown on Berberis Fendleri without 

 infection. In most of these cases the teliospores germinated 

 weakly, and this may account, in part at least, for the negative 

 results. 



A careful comparison was made of the material obtained from 

 the above cultures with the type of P. montanensis. It was found 

 that all the material, shown by these cultures to be connected with 

 aecia on Berberis Fendleri, agreed closely with the type of P. mon- 

 tanensis. The uredinia are cinnamon-brown and are provided 



