38 Aveneae 



Tribe 5. AVENEAE. OAT TRIBE. 



Spikelets 2-several-flowered ; outer empty glumes 

 usually longer than the first flowering glume ; 1 or more 

 of the flowering glumes awned on the back or from be- 

 tween the teeth of the bifid apex ; awn usually twisted 

 or geniculate. 



Spikelets articulated with the pedicels below the empty glumes. 



19. HOLCUS. 



Spikelets not articulate below the empty glumes. 

 Awns dorsal. 



Spikelets small, less than 1 cm. long. 20. DESCHAMPSIA. 



Spikelets 1 cm. long or more. 21. AVENA. 



Awns terminal, rising from between the lobes or teeth. 



22. DANTHONIA. 



19. HOLCUS L. VELVET-GRASS. 



Annual or perennial grasses with flat leaves and spike- 

 like or open panicles. Spikelets deciduous, 2-flowered ; 

 lower flowers perfect, upper staminate. Glumes 4 ; the 

 2 lower empty, membranous, keeled, the first 1-nerved, 

 the second 3-nerved and often short awned ; flowering 

 glumes chartaceous, the upper ones bearing a bent awn. 

 Palea narrow, 2-keeled. Stamens 3. Styles distinct. 

 Grain oblong, enclosed in the glume. 



1. H. lanatus L. Densely and softly pubescent throughout; 

 culms 4-6 dm. high, erect, often decumbent at the base, simple; 

 sheaths shorter than the internodes ; ligule 1-2 mm. long ; leaves 

 3-8 cm. long, 4-10 mm. wide; spikelets 4 mm. long; empty 

 glumes white-vilious, the upper awn-pointed ; flowering glumes 

 2 mm. long, smooth and shining, the lower sparsely ciliate on the 

 keel, somewhat obtuse, the upper 2-toothed and bearing a hooked 

 awn below the apex. 



Santa Anita and Oak Knoll, McClatchie, Davidson. 



20. DESCHAMPSIA Beauv. HAIR-GRASS. 



Annual or perennial grasses with flat or convolute 

 leaves and contracted or open panicles. Spikelets 2- 



