HOW TO KNOW THE GRASSES 



18b. Panicle slender and spikelike, usually 5—15 cm. long, with more 

 than 10 spikelets. Fig. 56. 



Tildens muticus (Torr.) Nash 



Figure 56 



Perennial; tufted; culms 30 — 50 cm. tall. 

 The spikelets often have a faint purplish hue 

 before drying. Leaf blades very narrow, 

 about 1 mm. wide. Overgrazed lands and 

 dry rocky slopes. Forage value low. June — 

 October. Also known as Triodia mutica. 



Tridens elongatus (Buckl.) Nash is very 

 similar, but has leaf blades up to 3 — 4 mm. 

 wide; plants 40 — 80 cm. tall; panicles 10 — 25 

 cm. long. Missouri to Texas and Arizona. 



19a. Lemmas split at the tip. Fig. 57 17b 



19b. Lemmas not split at the tip. 



20 



Figure 57 



20a. Grain large, bottle-shaped, 5 — 6 mm. long, forcing the stiff, strong- 

 ly-keeled lemma and the palea apart at maturity and protruding 

 between them. Fig. 58. 



Diarrhena aznericana Beouv. 



Perennial; producing numerous scaly 

 rhizomes; culms up to a meter in height; 

 leaves mostly low on the culm, the blades 

 1 — 2 cm. wide, scabrous or hairy; panicle 

 slender, with short erect branches, nodding, 

 10—30 cm. long. Spikelets 10 — 18 mm. 

 long. Growing in scattered clumps in 

 rich woods. The pecuHarly shaped grains 

 are unique among our grasses. July — 

 October. 



Figure 58 



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