25 



Tribe III.— OSTERDAMIJE. 



Spikelets solitary or in groups of 2 to 8, each group falling as a 

 whole from the continuous rachis, usually 1-flowered, hermaphro- 

 dite, or staminate and hermaphrodite in the same group; flowering 

 glume less firm in texture than the awned or awnless outer ones, 

 which are herbaceous, chartaceous, or coriaceous; the first glume 

 is usually larger than the second. 



A small tribe, numbering about 25 species, which 

 represent nearly half that number of genera. Fifteen 

 species are natives of the tropical and warmer temper- 

 ate regions of America. Black grama, or Galleta, of 

 the Mexicans, is our best-known representative of the 

 tribe. 



KEY TO THE GENERA OF THE OSTERDAMI.E. 



1. Spikelets solitary, empty glume one, coriaceous, awnless. 



17. OsTERDAMIA 



1. Spikelets in clusters of from three to several at each joint of the 



main axis, empty glumes two 2 



2. Second empty glume coriaceous with hooked spines oii the 



back ■_ 16. Nazia 



2. Second empty glume without hooked spines on the back 3 



3. Spikelets secund along the main axis, the lower spikelets in 



each group sterile 15. ^Egopogon 



3. Spikelets not secund along the main axis, the two lower or 

 outer spikelets 2-flowered and staminate 14. Hilaria 



