HOW TO KNOW THE GRASSES 



WILD OATS 



10b. Awn attached on the back of the lemma; spikelets with 2 or 3 

 florets. Fig. 185. 



Avena iatua L. 



Annual; culms usually 30 — 100 cm. tall, in 

 small tufts; panicles open, up to 30 cm. long. 

 The spikelets when ripe are open, bell-shaped, 

 with conspicuous protruding bent awns. The 

 scar at the base of the floret is circular and 

 prominent and is usually called a "sucker 

 mouth." Wild oats is distinguished by the 

 hairy lemmas, prominent awns' and the sucker 

 mouth. It is widely dispersed in the United 

 States but is most common in the Pacific Coast 

 States, where it is a prevalent weed and is 

 sometimes cut for hay. May — August. 



::io 



Figure 185 



Avena sativa L. (CULTIVATED OATS) Fig. 

 186 differs from wild oats in having lemmas 

 which are glabrous except on the callus, no 

 sucker mouth, and weak, usually straight 

 awns. Widely cultivated and growing from 

 scattered seed on roadsides and waste ground. 



Figure 186 



11a. Lemmas glabrous except for the hairy edges and callus; plants of 

 the western mountains. Fig. 187. 



Danthonia caWornica Bolander 



Perennial; tufted; culms 30 — 80 cm. tall, 

 tending to break at the joints. The panicle 

 is small, consisting of 2 — 5 large spikelets 

 on spreading pedicels. In this and other 

 species of Danthonia, the lower sheaths 

 may be swollen and contain slender, much 

 distorted cleistogamous spikelets called 

 "cleistogenes." The culms break off just 

 below the node where a cleistogene is 

 present. Meadows and open woods. Of 

 some value for forage. May — August. 



Danthonia intermedia Vasey has the few 

 spikelets borne in a dense, tuft-Hke panicle, 

 2 — 5 cm long. Arctic North America, south- 

 ward to Michigan and at high altitudes in 

 Grazed by livestock. July — September. 



Figure 187 



western states. 



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