Plants annual or weakly perennial. Culms 5-170 cm, hollow. Sheaths glabrous or scabrous; ligules 2-8 mm, membranous, attenuate, becoming lacerate at maturity; blades 3-50 cm long, 2-7 mm wide, glabrous or scabrous, those of the flag leaves sometimes exceeding the panicles. Panicles (1.5)10-105 cm long, 0.5-22 cm wide, with 3-35 racemose branches, bases of the panicles sometimes remaining enclosed in the upper leaf sheaths at maturity; branches 1.5-20(22) cm, ascending to reflexed. Spikelets 5-12(14) mm, with 6-20 florets. Lower glumes 1-3(4.9) mm; upper glumes 1.8-5.5 mm; lemmas 2-6 mm, sometimes with a dark spot near the base, apices acute to truncate, sometimes emarginate to bifid, unawned, mucronate, or awned; paleas somewhat sericeous along the veins; anthers 1-3, 0.2-2.7 mm. Caryopses 0.8-2.4 mm, elliptic to ovate or obovate. 2n = 20.
Mo., N.J., Conn., N.Y., Wash., Del., D.C., Wis., Pa., W.Va., Maine, N.H., Pacific Islands (Hawaii), Fla., Wyo., Puerto Rico, N.Mex., Tex., La., N.C., Mass., Tenn., Ariz., Calif., Virgin Islands, R.I., Nev., Va., Colo., Miss., Oreg., Ala., Kans., N.Dak., Nebr., Okla., S.Dak., S.C., Ark., Vt., Ill., Ga., Ind., Iowa, Idaho, Md., Ohio, Utah, Minn., Mich., Mont., B.C., Ont., Que., Ky.
Leptochloa fusca grows in warm areas throughout the world. The two American subspecies, subsp. uninervia and subsp. fascicularis, are usually distinct, but they intergrade repeatedly with L. fusca subsp. fusca.
|1||Uppermost leaf blades exceeding the panicles; panicles usually partially enclosed in the uppermost leaf sheaths; mature lemmas often smoky white with a dark spot in the basal 1/2||Leptochloa fusca subsp. fascicularis|
|1||Uppermost leaf blades exceeded by the panicles; panicles usually completely exserted; mature lemmas usually lacking a dark spot.||> 2|
|2||Anthers 0.5-2.7 mm long; spikelets 6-14 mm long; lemmas obtuse, acute, or acuminate, sometimes bifid, light brown to dark green||Leptochloa fusca subsp. fusca|
|2||Anthers 0.2-0.6(1) mm long; spikelets 5-10 mm long; lemmas obtuse to truncate, usually notched and mucronate, often dark green or lead-colored||Leptochloa fusca subsp. uninervia|