Plants cespitose, upper portion dense, oblong to oblanceolate or obpyramidal. Culms 20-250 cm; internodes green, sometimes glaucous; branches mostly erect, straight. Sheaths usually scabrous, sometimes smooth; ligules 0.6-2.2 mm, sometimes ciliate, cilia to 0.9 mm; blades 13-109 cm long, 2.9-9.5 mm wide, glabrous or sparsely to densely pubescent, hairs usually spreading, rarely appressed. Inflorescence units 10-600 per culm; subtending sheaths (2.0)2.9-4.4(6.5) cm long, (1.5)2.3-3.4(4.4) mm wide; peduncles (1)6-14(60) mm, with 2(4) rames; rames(1)1.7-2.5(3.5) cm, exserted or not at maturity, pubescence sparse basally and increasing in density distally within each internode. Sessile spikelets 3-5 mm; callus hairs 1-2.5 mm; keels of lower glumes sometimes scabrous below midlength, usually scabrous distally; awns 6-19 mm; anthers 1(3), 0.5-1.5 mm, yellow, red, or purple. Pedicellate spikelets vestigial or absent, sterile. 2n = 20.
Andropogon glomeratus hybridizes with both A. longiberbis and A. virginicus. Some of its varieties are morphologically similar to the latter species.