UNITED STATES DEPARTMENT OF AGRICULTURE 
BULLETIN No. 772 
Contribution from the Bureau of Plant Industry 
WM. A. TAYLOR, Chief 
Washington, D. C. PROFESSIONAL PAPER March 20, 1920 
THE GENERA OF GRASSES OF THE 
UNITED STATES 
WITH SPECIAL REFERENCE TO THE ECONOMIC SPECIES 
By . 
A. S. HITCHCOCK, Systematic Agrostologist 
CONTENTS 
Page 
Scope and Plan of the Work 1 
Poaceae, the Grass Family 5 
Descriptions of the Subfamilies and Keys 
to the Tribes 6 
Descriptions of the Tribes and Keys to 
the Genera 8 
Descriptions of the Genera 22 
1. Bamboseae, the Bamboo Tribe . . 22 
2. Festuceae, the Fescue Tribe ... 24 
3. Hordeae, the Barley Tribe .... 87 
4. Aveneae, the Oat Tribe 106 
6. Agrostldeae, the Timothy Tribe . . 121 
6. Nazieae, the Curly-Mesquite Tribe . 165 
Paeg 
Descriptions of the Genera— Continued. 
7. Chlorideae, the Grama Tribe . . .171 
8. Phalarideae, the Canary-Grass Tribe 199 
9. Oryzeae, the Rice Tribe 204 
10. Zizanieae, the Indian-Rice Tribe . 206 
11. Melinideae, the Molasses - Grass 
Tribe 212 
12. Paniceae, the Millet Tribe . . . .213 
13. Andropogoneae, the Sorghum Tribe 252 
14. Tripsaceae, the Corn Tribe .... 280 
List of New Species and New Names . . 288 
Index 289 
WASHINGTON 
GOVERNMENT PRINTING OFFICE 
1920 
