THE AGRICULTURAL GRASSES OF THE UNITED STATES. 81 



grass must be mowed from three to five times every summer. Thus briers, broom 

 grass, and other weeds are repressed aud prevented from seeding, multiplying, and 

 ruining the meadow. 



Eespecting the difficulty of eradicatiug this grass from ground wanted 

 for other cultivation, Colonel Lane, of Georgia, says : 



Upon our ordinary upland I have found no difficulty in destroying it by close cul- 

 tivation in cotton for two years. It requires a few extra [)lo\viugs to get the sod thor- 

 oughly broken to pieces. 

 (Plate 75.) 



Chlokis alba. 



An annual grass, growing in tufts, 1 to 2 feet high, smooth, the culms 

 frequently branched and bent at the lower joints, decnmbent, becom- 

 ing erect; leaves numerous, smooth, the sheaths mostly loose, the blade 

 broad, the upper sheath dilated and at first inclosing the flower spikes, 

 which are eight to tifteen in numbei-, _} to 3 inches long, and umbellate 

 or fascicnlate at the top of the culm or of the lateral branches. The 

 spikelets are sessile and crowded in two rows on one side of the spikes ; 

 each spikelet contains one perfect and one or two imperfect or ludi- 

 nientary flowers; the outer glumes are unequal, thin, keeled, the uj)})er 

 one mucronate-pointecl, and about one and one-half lines loug, the lower 

 one oue-third shorter ; the- flowering glume of the lower or perfect flower 

 is thick and firm in texture, nearly one and one-half lines long, broad in 

 the middle and narrowed above and below, much compressed, Ave nerved, 

 with two short teeth at the apex, and a straight awn two or three lines 

 long between the teeth, the margins toward the top strongly ciliate with 

 long white hairs; the palet is of similar texture, narrow, and nearly as 

 long as its glume ; the neutral or upper flower is shorter, truncate above, 

 of a club-like appearance, smooth, tipped with an awn. Sometimes 

 there is another small imperfect flower or a pedicel above the second, 

 and enwrapped by it. 



This is a common grass in the arid regions of Xew Mexico, Arizona, 

 and farther south and west. This grass furnishes a large quantity of 

 foliage, but of its agricultural value we have no information. There 

 are several other species growing in the same region. (Plate 70.) 



BouTELOUA. (Mesquite grass.) 



This genus, of which there are many species, has generally numerous 

 spikes in a racemose one-sided panicle. The spikes are generally 

 densely flowered and from one-half to 14 inches long. The spikelets are 

 crowded in two rows on one side of the axis, each consisting of one per- 

 fect flower, and a stalked pedicel bearing empty glumes and one to three 

 stittawus; the outer glumes are unequal, acute, keeled, membranaceous; 

 the flowering glume broader and usually thicker, with three to Ave lobes, 

 teeth or awns at the apex ; palet hyaline, narrow, entire or two-toothed, 

 enfolded by its glume. 

 2218 GR 6 



