Plants annual or perennial; cespitose. Culms 15-150 cm, erect or decumbent and rooting at the lower nodes, erect distally; nodes glabrous or pubescent. Leaves mostly basal; sheaths stiffly pubescent; ligules of hairs or membranous and ciliate; blades linear to lanceolate. Inflorescences terminal, panicles of 4-11 digitate or subdigitate, spikelike branches; branches naked at the base, spikelets in pairs or triplets, lower lemmas and lower glumes closest to the branch axes; disarticulation below the glumes. Spikelets 2.5-7 mm, dorsally compressed, with 2 florets. Glumes acute to shortly awned; lower glumes about 1/2 as long as the spikelets, 1-2-veined; upper glumes equaling the spikelets, 3-5-veined, margins ciliate; lower florets staminate; lower lemmas papery; lower paleas reduced, deeply bifid, 1-veined; upper florets bisexual; upper lemmas stiffly membranous, margins involute, apices attenuate into a mucro or curved awn; anthers 3. Caryopses elliptic. x = 9. Name from the Greek allotrios, belonging to another and opsis, appearance, the spikelets and inflorescence resembling those of Panicum.