106 



Fig. 80. Bouteloua oligostachya (Nutt.) Torr. BLUE GRAMA.— a, The empty 

 glumes of a spikelet; b, a spikelet with the empty glumes removed, showing the 

 3-awned flowering glume, its palea, and the pedicellate 3-awned rudiment. 

 Figs. 194 to 207, in Bui. 7, and 500 to 502, in Bui. 17, illustrate other species of this 

 genus. 



80. BOUTELOTJA Lag. Varied. Cienc. Litt.Art. 2*: 141. 1805. Spikelets 1-to 

 2-flowered, numerous (rarely 2 or 3 or only 1) , crowded and closely sessile in 2 

 rows along one side of a continuous flattened rachis, which usually projects 

 beyond the spikelets; rachilla articulated above the empty glumes, the con- 

 tinuation beyond the hermaphrodite lower floret usually bearing a few rudi- 

 mentary glumes and 3 awns (rarely a staminate flower). Empty glumes 2, 

 unequal, the lower smaller, keeled; flowering glume broader, 3-nerved, 3-to 5- 

 toothed, or cleft, 3 of the divisions usually mucronate or awn-pointed. Palea 

 2-nerved and 2-toothed. Grain inclosed within the glume, but free. Usually 

 low annuals or perennials, with narrow and flat or convolute leaves, the uni- 

 lateral spikes few or many (rarely solitary) , and nearly sessile along a common 

 axis. 



Species about 30, all American, most abundant in the Southwestern States. 



