NATIVE GRASSES AND PUCCINIA GRAMINIS 181 



north into Minnesota ; northwest from central Hamilton county to 

 Buena Vista and Plymouth counties and westward into South 

 Dakota. It is abundant in Hancock, Winnebago, Kossuth, Palo 

 Alto, Dickinson, O'Brien, Osceola, Lyon counties in Iowa; Minne- 

 haha, Davison, Brookings, Codington, Grant and Roberts counties 

 in South Dakota ; Freeborn, Faribault, Jackson, Nobles, Martin, 

 Lyon, Yellow Medicine, Chippeway, Bigstone and Traverse counties 

 in Minnesota. Puccinia graminis is common on Macoun's Wild Rye 

 everywhere. It is one of the most commonly infected of the grass- 

 es in the region where it occurs. All of the culms are frequently 

 covered with the pustules of this rust from below the head to the 

 surface of the ground, close to the roots. This grass, like quack 

 grass and slender wheat grass, is a perennial. If there is any prob- 

 ability of the mycelium of this rust being perennial there is some 

 chance that P. graminis is carried over the winter on this host. It is, 

 however, I believe, an important factor in carrying the rust to some 

 of the cereals. 



Elymus canadensis is widely distributed throughout this region 

 from Illinois, Wisconsin, Minnesota, Kansas City, Missouri, and 

 Kansas City, Kansas, to Hamburg, Council Bluffs, Missouri Valley, 

 Sioux City, Iowa ; to Mitchell, Brookings and Watertown, South 

 Dakota; east to Graceville and Ortonville in western Minnesota to 

 Winona and Houston in eastern Minnesota. 



Elymus rohiistus Scrib and Smith. This large wild rye is the 

 most abundant of the species in the central prairie region of Iowa. 

 It occurs from western Illinois (Hamilton) and eastern Iowa to 

 Scales Mound, Illinois, and Dubuque, Iowa, north to La Crosse, 

 Wisconsin, to southeastern Minnesota and westward to Ortonville, 

 Minnesota ; Brookings and Mitchell, South Dakota ; south to Sioux 

 City and Hamburg, Iowa. Cultural experiments have shown that 

 P. graminis occurs on Elymus canadensis and E. robustus. The 

 writer found uredo pustules of what appear to be P. graminis on 

 the culms of Elymus cafiadensis at Sibley, Thompson and Spirit 

 Lake, Iowa. At Luverne, Minnesota, and La Crosse, Wisconsin, it 

 was found on E. robustus. The uredo sori were not numerous but 

 these observations were made early in August. I am satisfied that 

 the pustules may have increased in number later in the season. It 

 may be of interest to mention that at Sioux Falls and Mitchell, South 

 Dakota, and in northeastern Hancock county, Iowa, an abundance 

 of rust outwardly resembling P. graminis occurred on the Elymus 

 robustus. Elymus robustus was abundant but isolated at Ottumwa, 

 Burlington and Keokuk, Iowa, and Hamilton, Zearing and Walnut, 



