AVENE^ 209 



D. Awn arising from between the teeth of 

 the bifid apex, flattened, twisted; in- 

 florescence a simple panicle or reduced 

 to a raceme or even to a single spikelet.DANTHONiA. 

 DD. Awn dorsal. 



E. Lower floret of the 2-flowered spike- 

 let staminate Arrhenath- 



EE. Lower floret perfect. [erum (Par. 241). 



F. Spikelets large, the glumes over 



1 cm. long AvENA 



FF. Spikelets less than 1 cm. long. (Par. 239). 



G. Lemma keeled, bidentate; awn 



arising from above the middle.. Trisetum. 

 GG. Lemma convex; awn from below 



the middle Deschampsia. 



238. Notholcus Nash. — A genus of several species of 

 Europe and Africa, one of which, velvet-grass {N. lanatus), 

 is introduced in America. This is sometimes cultivated as 

 a meadow-grass but has little forage value. As it thrives 

 better than other meadow-grasses upon poor soil it is 

 utilized for sterile ground. It has escaped in many parts 

 of the United States especially on the Pacific coast. Velvet- 

 grass is an erect perennial with velvety foliage and a 

 narrow panicle, expanded in flower. (Holcus L. in part.) 



Notholcus lanatus (L.) Nash. (Fig. 4.3). Velvet-grass. Perennial; 

 culms erect, 1 to 3 feet high, pubescent; sheaths velvety especially- 

 near the node; hgule pubescent, membranaceous, about 2 mm. long, 

 more or less toothed and ciliate; blades flat, velvety, mostly 2 to 4 

 inches long; panicle oblong, 2 to 4 inches long, pale or purplish, in 

 flower spreading and rather open, in fruit contracted; spikelets 4 to 

 5 mm. long, the glumes pubescent, longer than the florets, ciliate 

 on the nerves, the upper broader, 3-nerved, the awn of the second 

 floret hooked. A common weed from Puget Sound to San Francisco, 

 in moist and dry soil. 



239. Avena L. — Oats. Mostly annuals with large 

 spikelets, of which the common cultivated oat {A. saliva) is 

 the most familiar example. The drooping spikelets are in 

 open panicles. The large and papery glumes are longer than 



N 



