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



FIGURE 525. Distribution of 

 Hordeum nodosum. 



FIGURE 527. Distribution of 

 Hordeum pusillum. 



6. Hordeum adscendens H.B.K. (Fig. 530.) Annual; culms 

 geniculate at base, 20 to 50 cm tall; spike erect, 3 to 6 cm long ex- 

 cluding awns; glumes all reduced to awns, scabrous, mostly 1.5 to 



2 cm long, somewhat 



spreading, the awn of the 



fertile floret as long as 



the glumes. Dry 



open ground, Arizona and 



and Mexico. 



7. Hordeum murinum 



L. MOUSE BARLEY. 



(Fig. 531.) Annual; 

 culms bushy-branched, spreading; sheaths and blades smooth; spike 

 5 to 7 cm long, often partially enclosed by the uppermost inflated 

 sheath; glumes of the central spikelet narrowly fusiform, 3-nerved, 

 long-ciliate on both margins, the nerves scabrous, 



the awn about 2.5 cm long; glumes of 



the lateral spikelets unlike, the inner 



similar to the central ones, the outer 



setaceous, not ciliate; lemmas all 



broad, 8 to 10 mm long, the awns 



somewhat exceeding those of the 



glumes, o Fields, waste places, 



and open ground, introduced from 



Europe ; here and there in the Eastern 



States from Maine to Alabama; com- 

 mon on the Pacific coast, Idaho and 



British Columbia, south to Utah, New 



Mexico, and California (fig. 532). 

 8. Hordeum vulgare L. BARLEY. 



(Fig. 533.) Annual; culms erect, 60 



to 120 cm tall; blades flat, mostly 5 



to 15 mm wide; spike erect or nearly 



so, 2 to 10 cm long, excluding awns; 

 glumes divergent at base, narrow, nerveless, gradually passing into a 

 stout awn; awn of lemma straight, erect, mostly 10 to 15 cm long. 

 O Cultivated for the grain, sometimes spontaneous in fields and 

 waste places but not persistent. There are two 

 groups of the cultivated barleys. In the 2- 

 rowed forms (H. distichon L.) the lateral spike- 

 lets are fairly well developed but sterile. The 

 probable ancestor for at least a part of these is 

 H. spontaneum Koch, of Asia. In the second 

 group all the spikelets produce large seed. 

 These are called 6-rowed (H. hexastichon L.) or, 

 if the lateral florets overlap, 4-rowed barleys 

 (in European literature). In some varieties the caryopsis is naked. 

 The ancestor of the 6-rowed barleys is not known but probably was 

 similar to some of our cultivated varieties of this group. HORDEUM 

 VULGARE var. TRIFURCATUM (Schlecht.) Alefeld, BEARDLESS BARLEY. 

 Awns suppressed or converted into irregular short lobes or teeth. 



FIGURE 526. 

 Hordeum pusil- 

 lum,Xl. (Hitch- 

 cock 11102, S. 

 Dak.) 



FIGURE 528. Hordeum 

 gussoneanum, X 1. 

 (Hitchcock 2688, Calif.) 



FIGURE 529. Distribution of 

 Hordeum gussoneanum. 





