240 MISC. PUBLICATION 200, U. S. DEFT. OF AGRICULTURE 



longer; spikelets 3- to 5-flowered, the rachilla internodes minutely- 

 scabrous, about 2 mm long; glumes narrow, one obscurely nerved, the 

 other with 2 or 3 distinct nerves, tapering into a divergent awn similar 

 to the awns of the lemmas; lemmas nerved toward the tip, tapering 

 to a strongly divergent awn 1.5 to 2.5 cm long; palea a little longer 

 than the body of the lemma, the apex with 2 short slender teeth. 

 21 — Alpine slopes, 3,000 to 4,000 m, Montana to northern New 

 Mexico, Nevada, and northern Arizona (fig. 464). Characterized by 

 the hard leafy basal tussock with slender spreading flexuous culms. 

 18. Agropyron spicatum (Pursh) Scribn. and Smith. Bluebunch 



WHEATGRASS. (Fig. 465.) 



Green or glaucous; culms 

 tufted, often in large bunches, 

 erect, 60 to 100 cm tall ; sheaths 



Figure 464.— Distribution of 

 Agropyron scribneri. 



glabrous ; blades flat to loosely 

 involute, 1 to 2 mm, some- 

 times to 4 mm wide, glabrous 

 beneath, pubescent on the 

 upper surface; spike slender, 



Figure 466.— Distribution of 

 Agropyron spicatum. 



mostly 8 to 15 cm long, the 

 rachis scaberulous on the 

 angles, 1 to 2 era long, or the FlG 

 lowermost 2.5 cm; spikelets 



distant, not as long (excluding the awns) as the internodes or 

 slightly longer, mostly 6- to 8-flowered, the rachilla joints 

 scaberulous, 1.5 to 2 mm long; glumes rather narrow, obtuse to 

 acute, rarely short-awned, about 4-nerved, usually about half 

 as long as the spikelet, glabrous or scabrous on the nerves; lemmas 

 about 1 cm long, the awn strongly divergent, 1 to 2 cm long; 

 palea about as long as the lemma, obtuse. % — Plains, dry slopes, 

 canyons and dry open woods, northern Michigan to Alaska, south to 

 western South Dakota, New Mexico, and California (fig. 466). A 

 smaller form with smaller spikelets, found in desert regions of the 

 Great Basin has been differentiated as A. vaseyi Scribn. and Smith. 

 A. spicatum var. pubescens Elmer. Culms and foliage pubescent. 

 % — Washington and Idaho. 



