MANUAL OF THE GRASSES OF THE UNITED STATES 



243 



ditional awns; palea about as long as 

 the lemma, obtuse or truncate. 21 

 — Dry or rocky slopes and plains, 

 western South Dakota to Washing- 

 ton, south to Utah, Arizona, and Cali- 

 fornia. 



23. Agropyron saundersii (Vasey) 

 Hitchc. (Fig. 327.) Culms erect, 60 to 

 100 cm. tall; blades flat or loosely in- 

 volute; spike erect, 8 to 15 cm. long, 

 mostly purplish, the rachis tardily 

 disarticulating; spikelets sometimes in 

 pairs near the middle of the spike, 1 

 to 1.5 cm. long (excluding awns), 2- 

 to 5-flowered; glumes variable, nar- 

 row with 2 nerves or wider with 3 to 

 5 nerves, the nerves strong and at 

 least the midnerve scabrous, the awn 

 1 to 5 cm. long, sometimes with a 

 short lateral awn near the base; lem- 

 mas scabrous, the awn straight, 2 to 

 5 cm. long. % {Elymus saundersii 



Figure 327. — Agropyron saundersii, X 1. (Type.) 



Vasey.) — Dry slopes, Colorado, Wyo- 

 ming, Idaho, Utah, Arizona, and 

 California. Only the 5 specimens of 

 the type collection from Veta Pass, 

 Colo., have spikelets with awns to 5 

 cm. long. In some specimens the 

 awns of the glumes vary from 5 to 16 

 mm. and those of the lemmas from 7 

 to 30 mm. {Elymus saundersii var. 



calif ornicus Hoover), and in others 

 from 10 to 20 mm. on the glumes and 

 15 to 35 mm. on the lemmas. 



43. TRITICUM L. 



Spikelets 2- to 5-flowered, solitary, 

 placed flatwise at each joint of a con- 

 tinuous or articulate rachis, the ra- 

 chilla disarticulating above the 

 glumes and between the florets or con- 

 tinuous; glumes rigid, keeled, 3- to 

 several-nerved, the apex abruptly 

 mucronate or toothed or with one to 

 several awns; lemmas broad, keeled, 

 very asymmetric, many-nerved, 

 abruptly pointed or awned. Low or 

 rather tall annuals, with flat blades 

 and thick spikes. Standard species, 

 Triticum aestivum. Triticum, the old 

 Latin name for wheat. 



1. Triticum aestivum L. Wheat. 

 (Fig. 328.) Culms erect, freely branch- 

 ing at base, 60 to 100 cm. tall; blades 

 1 to 2 cm. wide; spike mostly 5 to 12 

 cm. long; internodes of rachis 3 to 6 

 mm. long; spikelets broad, glabrous 

 or pubescent, long-awned to awnless; 

 glumes usually strongly keeled toward 

 one side, the keel extending into a 

 mucro, the other side usually obtusely 

 angled at apex. O {T. vulgare 

 Vill. ; T. sativum Lam.)— Commonly 

 cultivated; fields and waste places in 

 the vicinity of cultivated fields or 

 grain elevators, but not established. 



Spelt {T. spelta L.) and emmer (T. 

 dicoccum Schrank) are sometimes 

 cultivated for the grain, used for 

 stock feed, and for forage. In these 

 two species the rachis breaks up, each 

 joint bearing a spikelet which re- 

 mains entire, each floret permanently 

 enclosing the grain. In spelt the 

 spikelets are somewhat distant, ex- 

 posing the rachis, in emmer the spike- 

 lets are closely imbricate, scarcely 

 exposing the rachis. A large number 

 of varieties of wheat are in cultiva- 

 tion; the lemmas may be glabrous 

 or pubescent, the awns long or nearly 

 or quite wanting. 



On the basis of the number of 

 chromosomes the wheats and their 



