320 SYSTEMATIC BOTANY. 



spikelets mostly in pairs, 2-3-flowered, smooth ; glumes rough, lanceolate, 

 tipped with a short awn ; lower palea with a short awn. In damp thickets, 

 2-4 feet high. August. 



15. Hordeum. Spikelets i-flowered, with an awn-like rudiment 

 at base on the inner side, 3 at each joint of the rachis ; lateral ones often 

 abortive. Glumes 2, side by side, and not opposite, subulate. Lower 

 palea long-awned at apex. 



H. VULGARE {Barley}. Culm erect, smooth ; leaves broad-linear, nearly 

 smooth ; spike erect, thick ; spikelets all fertile ; glumes shorter than the 

 flowers ; lower palea very long-awned ; fruit arranged in 4-6 rows. Fre- 

 quently cultivated, 2-3 feet high. May. (T) 



1 6. Danthonia. Spikelets 3-8-flowered, in a spicate panicle. 

 Glumes 2, longer than the flowers. Lower palea nerved, 2-toothed at 

 apex, with a twisted awn arising from between the teeth ; upper palea 

 obtuse, entire, of 



D. SPICATA {Oat Grass). Culms slender, erect, ascending, tufted ; 

 leaves mostly radical, somewhat involute ; cauline leaves much shorter than 

 the radical ones, erect, with sheaths hairy at the throat ; panicle slender, 

 bearing a few, appressed, y-flowered spikelets ; lower palea hairy. In dry 

 fields, 1-2 feet high. June- July. 



17. A vena. Spikelets 2-7-flowered in panicles ; uppermost flower 

 imperfect. Glumes 2, large and somewhat unequal. Lower palea 

 rounded on the back, nerved, 2-toothed at apex, with a twisted or bent 

 awn on the back. 



A. SATIVA (Oaf). Culm erect, smooth ; leaves broad-linear, rough above ; 

 panicle loose, with slender, drooping branchlets ; spikelets 2-4-flowered, on 

 slender, drooping peduncles ; lower flower awned, rarely both awnless ; up- 

 per palea closely investing the grain. Valuable grain, 2-3 feet high. June. 



18. Holcus. Spikelets 2-3-flowered, in a contracted panicle. 

 Flowers pedicellate, shorter than the glume ; lowest flower neutral, 

 often wanting ; middle flower perfect, awnless ; upper staminate, with 

 its lower palea awned on the back. y. 



H. LANATUS {Velvet Grass). Culm and broad-linear leaves pale green, 

 covered with soft, velvety down ; panicle oblong, dense-flowered, whitish, 

 tinged with purple ; staminate upper flower with a recurved, short awn. In 

 wet meadows, io'-2o' high. June-July. 



19. Anthoxanthum. Spikelets 3-flowered, in a spicate panicle ; 

 lateral flowers neutral, consisting of I hairy palea, awned on the back ; 

 central flower perfect. Glumes 2, very unequal, the upper one larger 

 and equaling the flowers. ^ 



A. ODORATUM (Sweet Vernal Grass). Culm erect, slender ; leaves short, 

 pale green ; panicle spicate, oblong, with short, nearly simple branches ; 



