104 MISC. PUBLICATION 42 3, U. S. DEPT. OF AGRICULTURE 



1. Sitanion hystrix (Nutt.) J. G. Smith, U. S. Dept. Agr., Div. 

 Agrost. Bui. 18: 15. 1899. 



Aegilops hystrix Nutt., Gen. PL 1: 86. 1818. 



Apache, Navajo, and Coconino Counties, south to Cochise, Santa 

 Cruz, and Pima Counties, 2,000 to 11,500 feet, open sandy ground, 

 rocky hills, and open pine woods, March to September. South 

 Dakota to British Columbia, south to Missouri, Texas, Arizona, and 

 Mexico. 



Eaten when young by livestock. The mature awns penetrate the 

 flesh of grazing animals, causing inflammation. 



22. HORDEUM. Barley 



Annuals or perennials with flat leaf blades and dense, bristly spikes; 

 spikelets 1 -flowered, 3 at each node of the articulate rachis, the middle 

 one sessile, the lateral ones pedicelled, usually imperfect, sometimes 

 reduced to bristles; glumes narrow or subulate; lemmas with back 

 turned toward the rachis, rounded, obscurely nerved, tapering into 

 an awn. 



The wild barleys are grazed before maturity. Some of them are 

 aggressive weeds. The "beards" and the sharp joints of the spikes 

 injure stock by piercing their mouths and nostrils, and get into wool, 

 causing sores when they penetrate the skin. Common cultivated 

 barley is H. vulgare L. 



Key to the species 

 1. Plants perennial (2) . 



2. Awns 2 to 5 cm. long; spike nodding 1. H. jubatum. 



2. Awns mostly less than 1 cm. long; spike erect 2. H. nodosum. 



1. Plants annual (3). 



3. Glumes ciliate, except the outer ones of the lateral spikelets_ 3. H. mueinum. 

 3. Glumes not ciliate (4). 



4. Glumes of the central spikelet and first glume of the lateral spikelets 



dilated above the base 4. H. pusillum. 



4. Glumes not dilated, setaceous or reduced to awns (5). 



5. Culms freely branching, decumbent-spreading; glumes and awns stout, 



rigid 5. H. gussonianum. 



5. Culms nearly simple, geniculate but not decumbent-spreading at base; 

 glumes and awns slender 6. H. adscendens. 



1. Hordeum jubatum L., Sp. PL 85. 1753. 



Apache, Navajo, Coconino, and Maricopa Counties, up to 7,500 

 feet, a common weed in moist open ground, along ditches, and waste 

 places, June to September. Newfoundland to Alaska, south to 

 Maryland, Missouri, Texas, Arizona, and California. 



A form with awns 1.5 to 3 cm. long is var. caespitosum (Scribn.) 

 Hitchc. 



2. Hordeum nodosum L. ? Sp. PL ed. 2, 126. 1762. 



Apache, Coconino, Greenlee, Maricopa, Cochise, and Pima Counties, 

 up to 9,800 feet, meadows and open ground, June to October. Alaska 

 to Montana, south to New Mexico, Arizona, and California, introduced 

 in a few localities in the Eastern States. 



3. Hordeum murinum L., Sp. PL 85. 1753. 



Coconino, Pinal, Maricopa, Cochise, and Pima Counties, a weed in 

 cultivated ground and waste places, mostly April to June. Maine to 



