HOW TO KNOW THE GRASSES 



9a. Lemmas awnless or with straight awns. Fig. 166. 



Agropyron trachycaulum (Link) Steud. 



Perennial; tufted; culms 50—100 cm. tall- 

 spikes and spikelets slender; glumes conspicu- 

 ously nerved. Awned and awnless forms oc- 

 cur, often in the same stand of plants. This 

 is an important forage species in the western 

 mountains. Moist grassland and open woods. 

 As here discussed, this species includes what 

 are called A. pauciiloium (awnless) and A. suh- 

 secundum fawned). June — September. 



Figure 166 



9b. Lemmas with strongly bent awns. Fig. 167. 



BLUEBUNCH WHEATGRASS Agropyron spicatum (Pursh) S. & S. 



Perennial; tufted; cuhns 60 — 100 cm. 

 tall. The spikes are slender and deU- 

 cate. Sheaths smooth; blades 1 — 4 mm. 

 wide, hairy on the upper surface. This 

 species is one of the most abundant 

 and important forage species of the 

 northwestern states, and is readily eaten 

 at all seasons and by all kinds of Hve- 

 stock. Dry plains and open mountain 

 slopes. May — August. 



Figure 167 



10a. Spikelets with 1 floret; 3 spikelets at each node of the rachis, the 

 lateral pair sometimes reduced to awns 11 



10b. Spikelets with 2 or more florets, 2 or more spikelets at some or 

 all nodes; all spikelets alike and fertile 13 



11a. Rachis of spikes separating at maturity into individual joints, each 

 bearing 3 spikelets; wild plants 12 



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