THE AGRICULTURAL GRASSES OF THE UNITED STATES. 87 



the nerves ; the flowering glaiiies two-Iobed or two-cleft at the summit, 

 with the mid-uerve extended into a short awn between the lobes. This 

 grass has very little practical value. 



DiPLACHNE. {LeptocMoa.) 



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 LeptocMoa, the outer glumes keeled j 

 acute, but not awned ; 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. [Leptocliloa 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-tliirds 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 panicle 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-pointed j the flowering 

 are ovate-lanceolate, about one and a half lines long, flattish 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. {Leptocliloa duhin.) 



A grass of similar aspect to the preceding -, the leaves somewhat longer 

 and more rigid; the panicle 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 ner\'ed, smooth 

 except on the margins, awnless ; the palet 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 south westward. (Plate 

 S6.) 



