THE AGRICULTURAL GRASSES OF THE UNITED STATES. 87 



the nerves ; the flowering gkimes two-lobed or two-cleft at the summit, 

 with the micl-Derve extended into' a short awn between the lobes. This 

 grass has very little practical value. 



DiPLACHNE. {Lej)tochloa.) 



This genus is characterized as having the spikelets narrow, sessile, 

 or nearly so, on the long slender branches of the panicle, usually in two 

 rows, but not continuous as in Leptocliloa^ the outer glumes keeled? 

 acute, but not awned j the flowering glumes one to three nerved, with a 

 thin or hyaline, shortly two-toothed or two-lobed apex, the keel pro- 

 duced into a short point or awn between the lobes ; palet thin and 

 prominently two-nerved. 



DiPLACHNE FASCICULARIS. (Leptochloa fascicular IS.) (Spike grass.) 



An annual grass of vigorous growth, 2 to 3 feet high, growing in brack" 

 ish marshes or wet ground near the sea-coast, and, also, far inland in 

 the Mississippi Valley, Texas, Arizona, &c , in alkaline soil. The radical 

 leaves are narrow and half to two-thirds as long as the culms, rough on 

 the margin ; those of the culms similar, with long, smooth, loose sheaths, 

 the upper one usually inclosing the base of the panicle. The culms are 

 frequently branched at the lower joints. The i)anicle is large, 6 to 10 

 inches long, consisting of numerous (fifteen to thirty) spike-like branches, 

 which are 2 to 4 inches long, mostly alternate, sometimes fascicled be- 

 low, angular and rough, and flower-bearing throughout. The spikelets 

 are nearly sessile and alternate, usually somewhat longer than the space 

 between them ; each contains five to seven flowers ; the outer glumes 

 are unequal, smooth, one-nerved, and mucronate-pointedj the flowering 

 are ovate-lanceolate, about one and a half lines long, flatfish on the back, 

 three-nerved, pubescent on the nerves and margins below, shortly two- 

 toothed at the apex, with a short rough awn between the teeth ; the 

 palet is somewhat shorter, lanceolate, two-nerved, and ciliate on the 

 nerves. (Plate 85.) 



DiPLACHNE DUBIA. {Leptockloa duMa.) 



A grass of similar aspect to the preceding ; the leaves somewhat longer 

 and more rigid; the i)anicle rather shorter, and composed of six to twelve 

 branches, which are stouter and more spreading. The outer glumes are 

 lanceolate, nearly equal, acute, one-nerved, rough on the keel, about one 

 and one-half lines long; the flowering glumes are oblong, very obtuse, two- 

 lobed and somewhat fringe-toothed at the apex, three nerved, smooth 

 except on the margins, awnless ; the i^alet is as long as its glume, nar- 

 rower, two-nerved, and ciliate on the nerves. The spikelets in age be- 

 come, spreading, and the axis zigzag. It is of more southern range than 

 he preceding, occurring in the Gulf States and southwestward. (Plate 

 86.) 



