172 



Fig. 166. AVENA MORTONIANA Scribn. Bot. Gaz. 21 : 133. 1896. MOR- 

 TON'S OAT-GRASS.— A densely csespito.se, erect perennial 1-2.5 dm. (4'-10') 

 high, with rather rigid leaves and narrow, simple panicles of 1- to 2-flowered 

 spikelets which are about 10 mm. (.5") long: empty glumes (a) lanceolate-acute, 

 the first 1-nerved, the second 3-nerved; flowering glumes (6) 8-9 mm. (i"-4^'>) 

 long, glabrous or scabrous above: callus den.sely pilose; awn twisted below, 

 scabrous, 14-16 mm. (7"-8") long.— At 3,900 to 4,200 m. (ll,700O-12,600°) altitude,' 

 mountains of Colorado. August. 



Allied to ^. amer/caHa Scribn., from which it is distinguished by its smaller 

 habit, shorter panicles, and smaller, fewer-flowered spikelets. 



