268 MISC. PUBLICATION 200, U. S. DEPT. OF AGRICULTURE 



Rachis disarticulating; lateral spikelets pedicellate. 



Floret of lateral spikelets longer and broader than that of central spikelet; rachis 



internodes mostly 3 mm. long 9. H. lepoeixum. 



Floret of lateral spikelets not larger than that of central spikelet; rachis internodes 



mostly 2 mm. long. 10. H. stebbixsii. 



Blades without auricles. 



Glumes of the fertile spikelet dilated above the base 5. H. pusillum. 



Glumes of the fertile spikelet not dilated. 



Awns slender, 1.5 to 2 cm. long, fragile; one glume of lateral spikelets slightly dilated. 



6. H. AEizoxicrjM. 

 Awns relatively stout. 



Floret of lateral spikelets awnless; glumes slender, not rigid, not bowed out. 



7. H. DEPEESSUM. 



Floret of lateral spikelets awned; glumes thickened and slightly bowed out below, 

 rigid 8. H. hystrix. 



1. Hordeum montanense Scribn. 

 (Fig. 361.) Culms 60 to 100 cm. tall; 

 sheaths glabrous; blades flat, lax, sca- 

 brous, 5 to 8 mm. wide; spike nodding, 

 8 to 17 cm. long; central spikelets usu- 

 ally 2-flowered, with a rudiment of a 

 third floret; lateral spikelets sessile, 

 usually well developed; glumes 

 slightly broadened above the base, 1 

 to 3.5 cm. long including awns; lower 

 floret of central spikelet about 8 mm. 

 long, the awn 1.5 to 3.5 cm. long. 

 % ( H. pammeli Scribn. and Ball.) — 

 Prairies, Illinois, Iowa, South Dakota, 

 Montana, and Wyoming. Variable 

 and somewhat anomalous; lateral 

 spikelets sometimes with 2 florets. 

 Approaches Ely mas; specimens re- 

 ferred by geneticists to hybrid Hor- 

 deum jubatum X Elymus virginicus. 



2. Hordeum jubatum L. Foxtail 

 barley. (Fig. 362.) Perennial, tufted; 

 culms erect, or decumbent at base, 30 

 to 60 cm. tall; blades 2 to 5 mm. wide, 

 scabrous; spike nodding, 5 to 10 cm. 

 long, about as wide, soft, pale; lateral 

 spikelets reduced to 1 to 3 spreading 

 awns; glumes of perfect spikelet awn- 

 like, 2.5 to 6 cm. long, spreading; 

 lemma 6 to 8 mm. long with an awn 

 as long as the glumes. % — Open 

 ground, meadows and waste places, 

 Newfoundland and Labrador to 

 Alaska, south to Maryland, Missouri, 

 Texas, California, and Mexico; intro- 

 duced in the Eastern States. A trou- 

 blesome weed in the Western States, 

 especially in irrigated meadows. Hor- 

 deum JUBATUM Var. CAESPITOSUM 



(Scribn.) Hitchc. Bobtail barley. 

 Awns 1.5 to 3 cm. long. (H. caespi- 



Figitre 361. — Hordeum montane?ise, X 1. (V. H. 

 Chase 1467. 111.) 



tosum Scribn.) North Dakota to 

 Alaska, south to California and Ari- 

 zona; Mexico. 

 3. Hordeum brachyantherum Nev- 



ski. Meadow barley. (Fig. 363.) 

 Perennial, tufted; culms erect Or as- 

 cending, 20 to 70 cm., sometimes to 

 100 cm., tall; lower sheaths thin, often 

 shredded, softly retrorse-pubescent to 

 glabrous; blades 3 to 8 mm., mostly 3 

 to 6 mm., wide, spike erect or slightly 

 nodding, 8 to 10 cm. long, rarely 

 longer, sometimes purplish; floret of 

 central spikelet usually 7 to 10 mm. 

 long, typically 1.5 mm. wide, the awn 

 about 1 cm. long, the glumes slightly 

 shorter; glumes of lateral spikelets 

 usually unequal, somewhat shorter, 

 the floret from well developed and 

 staminate to much reduced and 

 empty (occasionally a staminate and 



