Plants perennial; cespitose, not rhizomatous. Culms 60-170 cm, mostly smooth, scabrous beneath the panicles; basal branching intravaginal; prophylls longer than the sheaths, 2-awned, awns 2-3 cm, velutinous; nodes concealed by the sheaths. Leaves basally concentrated; cleistogenes not developed; sheaths open to the base, smooth, glabrous or hairy, hairs sometimes curly, margins extending into 2 awnlike extensions; auricles absent; ligules truncate, velutinous; blades conduplicate or convolute, about 1 mm in diameter. Inflorescences panicles, contracted, erect. Spikelets 26-30 mm, with 1 floret; rachillas not prolonged beyond the base of the floret; disarticulation above the glumes, beneath the floret. Glumes exceeding the floret, linear to lanceolate, gradually attenuate; florets 9-12 mm, terete; calluses well developed, sharp; lemmas thickly membranous to somewhat indurate, tan to brown, pubescent, margins flat, not overlapping at maturity, apices bifid, awned from between the teeth, teeth 1-6 mm, linear, scarious, awns once-geniculate, first segment twisted, terminal segment straight, scabrous; paleas equaling or exceeding the lemmas, pubescent, 2-veined, not keeled over the veins, flat between the veins, veins terminating before the apices, apices scarious, thinner than the palea body; lodicules 3, glabrous, ovate, acute, posterior lodicule smaller than the lateral lodicules; anthers 3, 10-15 mm, penicillate; ovaries glabrous; style 1, with 2 pilose branches. Caryopses fusiform; hila linear, about as long as the caryopses. x = 8. Name from the Greek makros, 'long', and chloa, 'grass'.