GRASSES OF IOWA. 319 



rine) ; 3344 .Marathon (Roberts); 3184 Elgin (Patterson) ; Emmet 

 County, Armstrong (Cratty) ; Lyon County (Macbride) ; Rock 

 Rapids, Spirit Lake (Shimek) ; Ames (Bessey). 



North America. Minnesota, Nebraska (Ravenna and Grand 

 Island, Pammel), Colorado (Colorado Springs, Pammel; Ft. Collins, 

 Crandall 49; Rouatt County, Shear and Bessey 1393), New Mexico, 

 I tali (East Duchesne River 235, Pammel and Stanton; Salt Lake City 

 and White Rock Agency, Pammel and Stanton; Black's Fork and Echo, 

 Pammel, Johnson, Buchanan and Lummis, 1573, 1578, 1581 and 1582), 

 Wyoming (Snake River, A. & E. Nelson, Burnt Fork and Sheridan, 

 24(1, 247, Pammel and Stanton), Washington (Sandberg and Leiberg 

 331 )• 



4. AGROPYRON OCCIDENTALE. 



Agropyron occidentale Scribner. N. Sp. 



Agropyrum spicatutn (Pursh.) Scribn. and Smith. Bull. U.S. Dept. 

 Agrl. Div. Agros. 3: 12. 1896. Scribner. Bull. U. S. Dept. Agrl. Div. Agros. 

 17: 298. f.594. 1899. 



Agropyrum Spicatum Scribn. and Smith. Shear. Bull. U. S. Dept. 

 Agrl. Div. Agros. 4: 33. 1897. 



DESCRIPTION. 



Colorado Blue Stem. Western Wheat Grass. A rigid, 

 upright, glaucous perennial, 1 to 4 feet (3-12 dm.) high, from creeping 

 root-stocks, with rather firm, bluish-green leaves, and straight, beard- 

 less spikes, 3 to 7 inches (6-14 cm.) long. Spikelets seven to thirteen- 

 flowered, 6 to 10 lines (12-20 mm.) long, with lanceolate, acuminate- 

 pointed, empty glumes, and acute flowering glumes 4 to 6 lines (8-12 

 mm.) long. Dry or moist soil. June to September. 



This species is widely introduced in Iowa, especially east of the 

 Missouri divide, except in Emmet, Palo Alto and Cerro Gordo 

 counties, where it is native. The Wisconsin localities are most likely 

 from introduced plants. It is one of the most abundant grasses of the 

 plain west of the Missouri river and east of the Rocky Mountains. It 

 covers wide stretches of the western plains forming a considerable part 

 of the herbage. It is a most valuable forage grass for the west. In 

 many parts of Iowa and Minnesota it is becoming a troublesome weed, 

 spreading with as much rapidity as quack grass. 



distribution. 



Iowa. 603 Denison, Mason City, 392 Elmore, Minn., Iowa-Min- 

 nesota line, 3308 Ceylon, 3268 Armstrong (Pammel) ; Ames (Carver, 



