MANUAL OF THE GRASSES OF THE UNITED STATES 



241 



19. Agropyron inerme (Scribn. and Smith) Rydb. Beardless 

 wheatgrass. (Fig. 467.) Differing from A. spicatum in the awnless 

 spikelets. % (A. spicatum var. inerme Heller.)— Dry plains and 

 hills, Montana to British Columbia, south to Utah, Wyoming, 



Figure 467.— 

 Agropyron 

 inerme, X 1. 

 (Horner 571, 

 Wash.) 



Figure 468.— Distribution of 

 Agropyron inerme. 



Figure 469.— Agropyron arizonicum, 

 X 1. (Type.) 



Figure 470.— Distribution of 

 Agropyron arizonicum. 



western Nebraska, and eastern Oregon (fig. 468). Closely related 

 to A. spicatum but very different in appearance because awnless. 



20. Agropyron arizonicum Scribn. and Smith. (Fig. 

 469.) Resembling A. spicatum, usually taller and 

 coarser; blades commonly 4 to 6 mm wide; spike 15 to 

 30 cm long, flexuous, the rachis more slender; spikelets 

 distant, mostly 3- to 5-flowered; glumes short-awned; 

 awns of the lemmas stouter, mostly 2 to 3 cm long. 

 % — Rocky slopes, western Texas, New Mexico, Arizona, 

 Nevada, California (Eel Ridge), and Chihuahua (fig. 470). 



Agropyron semicostatum (Steud.) Nees. Blades flat; 

 spike nodding, 10 to 20 cm long; spikelets several-flowered, 

 imbricate; glumes several-nerved, much shorter than 

 the spikelet, acute but scarcely awned; awn of lemma 

 flexuous or finally divergent, 1.5 to 3 cm long. 21 — 

 Ballast near Portland, Oreg. Native of Asia. 



21. Agropyron parishii Scribn. and Smith. (Fig. 471.) 

 Culms 70 to 100 cm tall, the nodes retrorsely pubescent; 

 blades flat or loosely involute, 2 to 4 mm wide; spike 

 slender, nodding, 10 to 25 cm long, the internodes of 

 the rachis 1.5 to 2.5 cm long; spikelets 4- to 7-flowered, 

 mostly about 2 cm long, narrow, appressed, the rachilla 



joints scaberulous, about 2 mm long; glumes 3- to 5-nerved, 1 to 1.5 

 cm long, acute ; lemmas acute or with a slender awn 1 to 8 mm long ; 

 palea as long as the lemma, obtuse. 91 — Canyons and rocky slopes, 

 California (Monterey and San Bernardino Mountains) ; rare. Agro- 



FlGURE 471.— 



Agropyron 

 parishii. X 1. 

 (Type.) 



