HOW TO KNOW THE GRASSES 



20b. Plants 20 — 50 cm. tall; leaf blades with blunt tips. Fig. 266. 



WINDMILL GRASS Chloris veTticillata Nutt. 



Perennial; culms tufted or with short 



stolons; leaf sheaths flattened and 

 keeled; ligule membranous and ciliate, 

 short; leaf blades grayish-green, 1 — 3 

 mm. wide; panicles of 2 or 3 whorls of 

 stiff, widely-spreading spikes, each 5 — 

 15 cm. long. Spikelets rather widely 

 spaced, the spikes slender; spikelets 

 around 3 mm. long; awns 5 — 8 mm. 

 long; fertile lemma hairy on the nerves; 

 rudimentary lemma blunt. Windmill 

 grass is primarily a plant of the plains 

 of the Southwest, but may appear occa- 

 sionally as a waif in the North. The 

 mature panicles break off and roll as 

 tumble weeds. June — September. 



Figure 266 



21a. Inflorescence of 1 — 10 spikes, which remain on the plant; florets 

 dropping from the glumes 22 



21b. Inflorescence of numerous spikes, arranged in a slender raceme; 

 entire spikes falling from the rachis whole when ripe. Fig. 267. 

 SIDE-OATS GRAMA Bouteloua curtipendula (Michx.) Torr. 



Figure 267 



Perennial; culms in tufts, arising from 

 slender rhizomes. The plants range up to 

 80 cm. in height, most of the height being 

 the long raceme of drooping spikes. Late 

 in the season all of the spikes drop from 

 the flattened rachis, which remains, bear- 

 ing only the short stalks of the spikes. 

 Side-oats is a very attractive grass, with 

 brilHont orange anthers, contrasting with 

 the usually purple spikes. The name "side- 

 oats" refers to the fact that most of the 

 spikes droop toward one side of the rachis. 

 This is one of the most valuable forage 

 grasses in the western states, furnishing 

 good feed yearlong. Dry plains and open 

 rocky hillsides, from near sea level to 

 2700 m. June — September. 



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