Plants perennial; loosely cespitose. Culms 65-150 cm, sometimes thickened at the base, erect, unbranched; internodes glabrous; nodes concealed. Leaves cauline; sheaths longer than the internodes, usually lanose-floccose, occasionally glabrate; ligules about 0.1 mm; blades 10-25(30) cm long, 2-6 mm wide, flat, light green or slightly blue-green, glabrous abaxially. Inflorescences paniculate, (25)35-70(82) cm long, (2)3-8(10) cm wide; rachis nodes lanose-floccose; primary branches 3-12 cm, appressed at the base, without axillary pulvini, ascending to spreading distally, sometimes loose and somewhat flexible, with 4-12 spikelets per branch. Glumes usually unequal, 1-veined, brownish-green to dark brown or purplish; lower glumes 8.7-18 mm, with a keeled mid-vein; upper glumes 8.4-15 mm, awn-tipped, awns to 3 mm; calluses 0.5-1 mm; lemmas 6.5-10 mm, smooth to scabridulous, mostly dark purplish-mottled, slightly narrowed distally but not beaked, junction with the awns not evident; central awns 12-28 mm, curved at the base, often strongly so; lateral awns 7-17 mm, at least Yi as long as the central awns; anthers 3, about 3 mm, brown. Caryopses 5-6 mm, chestnut brown. 2n = unknown.
Md., N.J., Okla., Miss., Tex., La., W.Va., Mo., Del., Ala., Tenn., N.C., S.C., Va., Ark., Ill., Ga., Fla.
Aristida lanosa is restricted to the eastern United States, where it grows in dry fields, pine-oak woods, and uplands, chiefly in sandy soil. It is sometimes confused with A. palustris, but differs in several reproductive, vegetative, and habitat characteristics.