AVENEM 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. 43). Velvet-grass. Perennial; 

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

 near the node; ligule 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 



