Plants annual or perennial; cespitose, sometimes rhizomatous. Culms 50-300+ cm, erect, nodding or clambering, unbranched; nodes densely pubescent, particularly in young plants. Leaves not aromatic; ligules membranous, glabrous or pubescent; blades flat, involute, or folded. Inflorescences terminal, secund or equilateral panicles with evident rachises and numerous branches, not subtended by modified leaves; branches capillary, rebranching, with many rames, not subtended by modified leaves; disarticulation in the rames, beneath the sessile spikelets. Spikelets sessile, subtending a hairy pedicel (2 pedicels in the terminal spikelet units), dorsally compressed. Calluses blunt or sharp; glumes coriaceous; lower glumes pubescent, 5-9-veined, acute; upper glumes slightly longer, usually glabrous, 5-veined, truncate; lower florets reduced to hyaline lemmas; upper florets bisexual, lemmas hyaline, bifid, awned from the sinuses; awns usually once- or twice-geniculate, often spirally twisted, shortly strigose, brownish; anthers 3; ovaries glabrous. Caryopses flattened. Pedicels 3-6.5 mm, slender, not fused to the rame axes; pedicellate spikelets absent. x = 10. Name from Sorghum and the Latin suffix astrum, a poor imitation of, alluding to its similarity to Sorghum.