152 HORDEAE 



Spikelets 2-to many-flowered. 



Rachis of tlie spikes jointed, readily 



breaking into joints. 7i'. Sitanion. 



Rachis of the spikes continuous, not 



breaking at the joints. 71. Elymus. 



Triticnm repens has been reported from two localities in New 

 Mexico by Rothrock but we have not seen specimens. 



68. AGROPYRON Gaertn. Wheat Grasses. 



Rachis of the spike breaking up at maturity, 



the joints falling with the spikelet. 1. a. scribneri. 



Rachis of the spike continuous. 



Awns of the flowering glumes conspicuous. 

 Awns divergent. 

 Spikelets subterete. i. e. nearly cylindric, 



more or less crowded. l'. A. bakeri. 



Spikelets flattened, not crowded. 

 Leaves rough hairy (scabrous-pubes- 

 cent) above; empty glumes acute 



o*" obtuse. ;; ,1. arizonicum. 



Leaves smooth, not hairy; empty 



glumes acuminate or awn-pointed. 4. .4. spicatitm. 

 Awns erect, not divergent. 

 Awns short, sometimes wanting; spike 



mostly purple tinged. ,;. A. violaceum. 



Awns longer, usually longer than the 

 body of the flowering glume. 

 Stems stout: spike 7 to 10 mm. wide, 

 erect but usually one-sided: spike- 

 lets (excluding the awns) 12 to 15 



mm. long. ,; .4 richardsonii. 



Stems slender; spikes about 5 mm . wide, 

 usually nodding, seldom one-sided; spike- 

 lets (including the awns) about 10 mm. 



o'^S- T. A. cani7ium. 



Awns of the flowering glumes not conspicu- 

 ous. 



Plants bright green, not glaucous. s. A. tenerum. 



Plants conspicuously glaucous. 



Sheaths and flowering glumes at most, 



scabrous. <i. a. smithii. 



Sheaths and flowering glumes noticeably 



pubescent. Ki. a. palmeri. 



1. Agropyrpn scribneri Vasey. Known in New Mexico 

 from one specimen from the top of the Las Vegas range. On high 

 mountains in the ITudsonian and Arctic-alpine Zones. 



2. Agropyron bakeri E. Nelson. Also on high peaks in the 

 Hudsonian Zone. 



