364 
Journal of Agricultural Research 
Vol. XXV, No. 9 
Stripe rust has been found in the western part of the United States on 
wheat, barley, rye, spelt, and emmer in the field, and upon 33 wild grasses. 
The wild grass hosts found naturally infected include seven species 
of Agropyron: A. spicatum (Pursh) Scribn. & Smith, A. cristatum (L.) 
Gaertn., A . dasystachyum (Hook.) Scribn., A. intermedium (Host) Beauv., 
A. violaceum (Hornem.) Lange, A. lanceolatum Scribn. & Smith; eight 
species of Bromus: B. marginatus Nees, B. pacificus Shear, B. sitchensis 
Trin., B. carinatus Hook. & Arn., B. carinatus hookerianus (Thurb.) 
Shear, B . rubens L., B. brizaeformis Fisch. & Mey., and B. polyanthus 
Scribn.; six species of Elymus: E. canadensis L., E. condensatus Presl, 
E. glaucus Buckl., E. macounii Vasey, E. striatus Willd., and E. virgin- 
icus L.; six species of Hordeum: H. jubatum L., H. gussoneanum Pari., 
H . murinum L., H. nodosum L., H. pusillum Nutt., and H. caespitosum 
Scribn.; two species of Hystrix: H. patula Moench., and H. californica 
(Boland.) Kuntze; three species of Sitanion: 5 . jubatum J. G. Smith, 5 . 
hystrix (Nutt.) J. G. Smith, and S. longifolium J. G. Smith; one species 
of Phalaris, P . paradoxa L., and one wild species of Triticum, T. aegilops 
Beauv. 
The rust has been found on wheat in nearly all the western States, but 
has been reported on barley from only four districts, viz: Eastern Wash¬ 
ington, eastern Oregon, western South Dakota, and central California. 
Only three collections have been made on rye, these being from 
northern Idaho, eastern Oregon, and western Oregon. The possible 
significance of the limited distribution of the rust on the last-named 
hosts will be discussed later. 
The occurrence of stripe rust on Bromus marginatus , Elymus canadensis , 
E. glaucus , Hordeum nodosum and H. jubatum has been found to be 
quite general within the known geographic limits of the various grasses 
and of the parasite. Hordeum murinum was very generally infected in 
1917 and in 1922 in the lower coast district of California, but has never 
been found so infected in other sections of the Pacific Coast where this 
host commonly occurs and where the rust has been present on other 
grasses. The collections on other hosts have been few in number and 
indicate that they are not as common hosts for the disease as the others 
already mentioned. In some cases, at least, they are more limited in 
their distribution. 
As will be shown in a forthcoming paper of this series of studies, 4 a num¬ 
ber of collections of stripe rust had been made prior to May, 1915, when 
stripe rust was first recognized in the United States. These had been 
identified as several other rusts. Among these collections appear two 
hosts which have not been found naturally infected since that time. 
They are Bromus carinatus hookerianus (Thurb.) Shear, and Sitanion 
longifolium J. G. Smith. 
The variety peculiar to wheat, Puccinia glumarum tritici Erikss. and 
Henn., has been found capable of infecting the following additional hosts 
when inoculations were made in the greenhouse: Agropyron tenerum Vas., 
and A.smithii Rydb.; Bromus hordeaceusl,-, B. inermis Leyss., B. commu- 
tatus Schrad., B. sterilis L., B. tectorum L., B. rigidus Roth, and B. ciliatus 
L.; Elymus australis Scribn. and Ball, and E . robustus Scribn. and Smith. 
A detailed discussion of the methods used and the results obtained in 
connection with the above determinations will be given later under the 
discussion of specialized races of P. glumarum. 
* In manuscript. 
