362 BROOKLYN BOTANIC GARDEN MEMOIRS 
It will be noted that the specialized races of groups I, II, and III 
have Rhamnus Imeretina as a common aecidial host. Rhamnus 
Purshiana also occurs as an aecidial host for races of groups IJ and III. 
It also appears that specialized races on Holcus and Agropyron occur 
in both groups I and IJ. In connection with the gramineous hosts 
certain specialized races also overlap. For example, Avena sativa is a 
host for specialized races Avenae, Alopecuri and Epigaet (Group 1); 
Festuca elatior is a host for specialized races Lolit and Festucae (Group 
1); 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. satwa nuda, 
A. fatua, A. pratensis, Alopecurus alpestris, Phleum pratense, Ph. 
asperum, Dactylis glomerata, Aira caespitosa, Holcus mollis, Eatonta 
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 caroliniana 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 festucacea 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.—A grostis stolontf- 
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, a host belong- 
ing to P. coronifera Kleb. Treboux’s tests with uredospores show the 
