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. 
Has been rev. 
—see rev.ecU 
binders at 
end of file. 
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 o f 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 
5 Agrostideae, the timothy tribe 121 
Page. 
Descriptions of the genera— Continued. 
6. Nazieae, the curly-mesquite tribe 165 
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 
SCOPE AND PLAN OF THE WORK. 
The present bulletin describes all the genera of grasses that include 
species that are native, have been introduced, or are cultivated in the 
United States. Under each genus are given the species that are 
of economic importance, either as useful or harmful grasses. Of all 
grasses the grains are of the greatest importance. Chief among other 
useful grasses are those that are cultivated for meadow or pasture 
and those indigenous species which furnish forage upon the native 
pasture or ranges. Other important grasses are the sugar-producing 
species, those used in broom or paper making, and the ornamental 
species. 
It is intended to give under each genus the botanical information 
concerning all our grasses that are conspicuous enough to have at- 
tracted the attention of agriculturists. The keys to the tribes and 
97769° — Bull. 772 — 20 1 
