MANUAL OF THE GRASSES OF THE UNITED STATES 



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adventive in Maine and Pennsylva- 

 nia; common westward, rare in the 

 Atlantic States; also southern South 

 America. Hordeum pusillum var. 

 pubens Hitchc. Spike broader; spike- 

 lets pubescent; dilated glumes wider. 

 O — Texas to Utah and Arizona. 



Figure 364. — Hordeum pusillum, X 1. 

 (Hitchcock 11102, S. Dak.) 



6. Hordeum arizonicum Covas. 

 (Fig. 365.) Annual; culms geniculate 

 at base, 20 to 60 cm. tall; lower 

 sheaths pubescent, the upper more or 

 less inflated; blades 3 to 5 mm. wide, 

 sparsely pubescent, the auricle want- 

 ing; spike erect, 3 to 12 cm. long; flo- 

 ret of central spikelet 8 to 9 mm. long, 

 1.5 mm. wide, the awn 15 to 22 mm. 

 long, the glumes slightly shorter; 

 glumes of lateral florets nearly as long, 

 one slightly dilated (all awns sca- 

 brous, slender, fragile, readily break- 

 ing); floret reduced to a small short- 

 awned lemma. (The name H. ad- 

 scendens has been misapplied to this 

 species.) O — Dry open ground 

 (large plants found along irrigation 

 ditches), Arizona and California 

 (Bard). 



7. Hordeum depressum (Scribn. 

 and Smith) Rydb. (Fig. 366.) Annual; 

 culms geniculate at base, commonly 

 spreading with ascending ends, 6 to 

 45 cm. long; upper sheaths often in- 

 flated; blades pubescent, mostly not 

 more than 5 cm. long (rarely to 15 

 cm.), 2 to 4 mm. wide, the auricle 

 wanting; spike erect, 4 to 7 cm. long; 

 floret of central spikelet 7 to 8 mm. 

 long, nearly terete, the awn about 10 

 mm. long; awns of the glumes and of 



Figure 365. 



-Hordeum arizonicum, X 1. (Thornber 

 536, Ariz.) 



Figure 366. — Hordeum depressum, X 3. (Type.) 



the glumes of lateral spikelets nearly 

 equal, the whole triad usually about 

 2 cm. long; floret of lateral spikelet 

 awnless. O — Mostly in moist al- 

 kaline soil or along rivers, also in arid 

 or sterile ground, sea level to 600 m., 

 Idaho and Washington to California. 



