362 BROOKLYN BOTANIC GARDEN MEMOIRS 



It will be noted that the specialized races of groups I, II, and III 

 have Rhamnus Inter etina as a common aecidial host. Rhamnus 

 Purshiana also occurs as an aecidial host for races of groups II and III. 

 It also appears that specialized races on Holcus and Agropyron occur 

 in both groups I and II. In connection with the gramineous hosts 

 certain specialized races also overlap. For example, Avena sativa is a 

 host for specialized races Avenae, Alopecuri and Epigaei (Group I); 

 Festuca elatior is a host for specialized races Lolii and Festucae (Group 

 I) ; Calamagrostis arundinacea, C. lanceolata and Phalaris arundinacea 

 are hosts for specialized races Calamagrostis and Phalaridis (Group II). 



Carleton (26), in this country, has tested the host relations of the 

 crown rust on oats. He finds that the rust on Avena sativa can be 

 transferred to Avena sativa patula, A. sativa orientalis, A. sativa nuda, 

 A. fatua, A. pratensis, Alopecurus alpestris, Phleum pratense, Ph. 

 asperum, Dactylis glomerata, Aira caespitosa, Holcus mollis, Eatonia 

 sp. indet., Koeleria cristata, Anthoxanthum odoratum, Festuca sp. indet., 

 Phalaris arundinacea, Polypogon monspeliensis , Trisetum subspicatum, 

 Brizopyron siculum and Poa annua. Carleton also transferred the 

 rust from Phalaris caroliniafta to Avena sativa and Dactylis glomerata. 

 The rust on Arrhenatherum elatius was also transferred to Avena sativa. 

 Aecidiospores from Rhamnus lanceolata readily infected Phalaris 

 caroliniana and Avena sativa. 



Arthur (6, 11, 14) reports the successful infection of Avena sativa 

 with .aecidiospores from Rhamnus lanceolata, Rh. caroliniana and Rh. 

 cathartica. He also succeeded in infecting Rhamnus alnifolia with 

 teleutospores from Calamagrostis canadensis. Teleutospores from 

 Holcus lanatus and Scolochloa jestucacea failed to infect Rhamnus 

 cathartica. 



Treboux (159, 160) reports the results of experiments with the 

 crown rust carried out in southern Russia which are quite at variance 

 with those obtained in Europe. He finds that aecidiospores from 

 Rhamnus cathartica obtained from a common source infected fifty- 

 one species of grasses belonging to the genera Alopecurus, Agropyron, 

 Agrostis, Aira, Arrhenatherum, Avena, Brachypodium, Briza, Bromus, 

 Calamagrostis, Dactylis, Eatonia, Festuca, Glyceria, Hierchloa, Holcus, 

 Hordeum, Koeleria, Lolium, Melica, Phalaris, Poa, Phleum, Poly- 

 pogon, Sclerochloa, Secale, Sesleria and Triticum. In these experi- 

 ments with Puccinia coronifera Kleb., Treboux obtained positive 

 results with three hosts of P.coronata (Corda) Kleb.— Agrostis stolonif- 

 era, Calamagrostis arundinacea and Phalaris arundinacea. Treboux 

 has also used the aecidiospores from Rhamnus Frangula to successfully 

 infect nine species of grasses, among them Avena sativa, sl host belong- 

 ing to P. coronifera Kleb. Treboux's tests with uredospores show the 



