MANUAL OF THE GRASSES OF THE UNITED STATES 



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Figure 409. — Helictotrichon pubescens. Glumes and 

 floret, X 5. (Weatherby and Harger 4249, Conn.) 



cm. long. 2[ — Alpine meadows, 

 Colorado, Utah, and New Mexico. 



63. ARRHENATHERUM Beauv. 



Spikelets2-flowered, the lower floret 

 staminate, the upper perfect, the ra- 

 chilla disarticulating above the 

 glumes and produced beyond the 

 florets; glumes rather broad and pa- 

 pery, the first 1-nerved, the second a 

 little longer than the first and about 

 as long as the spikelet, 3-nerved ; lem- 

 mas 5-nerved, hairy on the callus, the 

 lower bearing near the base a twisted, 

 geniculate, exserted awn, the upper 

 bearing a short straight slender awn 

 just below the tip. Rather tall peren- 

 nials, with flat blades and narrow pan- 

 icles. Type species, Arrhenatherum 

 avenaceum Beauv. (A. elatius). Name 

 from Greek arren, masculine, and 



Figure 411. — Helictotrichon mortonianum. Panicle, 

 X 1; floret, X 5. (Type.) 



Figure 410. — Helictotrichon hookeri. Panicle, X 1; 

 floret, X 5. (Scribner 372, Mont.) 



