238 



A TEXT-BOOK OF GRASSES 



guished from Triticum by the narrow pointed or awned 

 glumes. The American species are perennials. Couch- 

 grass, A. repens (L.) Beauv. (Fig. 58), is a troublesome 

 weed introduced from Europe. It prop- 

 agates by creeping rhizomes. A similar 

 native species, A. Smithii Rydb., is found 

 in alkali soil in the western states and 

 furnishes a fair quality of hay. Another 

 species, A. tenereum Vasey, is a bunch-grass 

 of the same region. This species has been 

 introduced into cultivation and is sold by 

 seedsmen under the name of slender wheat- 

 grass. This has erect stems 2 to 4 feet 

 high, with slender spikes 2 to 6 inches 

 long, or even longer, broad-nerved awn- 

 pointed glumes nearly as long as the spike- 

 let, and short-awned or awnless lemmas. 



263. Triticum L. Wheat. A small 

 genus of annuals distinguished from Agro- 

 pyron by the broad several-toothed or 

 awned glumes. The best known species is 

 the common wheat ( T. vulgaris; T. satwum) 

 of which there are numerous varieties. 

 'Those varieties bearing long awns are 

 called bearded wheats; those in which the 

 awn is short or none are called beardless 



FIG. 58. Agropyron repens. Inflorescence and 

 rhizomes, X}^; spikelet, X3. 



