Culms 40-150 cm, rather robust. Sheaths with the throat usually glabrous or sparsely pilose on the sides; ligules 0.3-1 mm, membranous; blades usually 5-12 mm wide, flat, mostly glabrous or scabridulous, bases about equal in width to the subtending sheaths. Panicles terminal and axillary, usually with many spikelets. Spikelets 1.6-2.5 mm long, usually over 0.6 mm wide, crowded, green or purplish-tinged, pedicellate, pedicels short, with 1-several slender hairs near the apices.
Panicum rigidulum subsp. rigidulum is the most common, most variable, and widest ranging of the five subspecies.