Plants annual or sometimes perennial; roots fibrous; rhizomes present in perennial forms, short. Culms solitary or in tufts, erect or spreading, slender, 20–90(–125) cm, glabrous or hairy. Leaves: sheaths often purplish tinged at base, sometimes somewhat winged, ribbed, glabrous or densely pubescent; contra-ligules rotund-obtuse, short; blades linear, flat, often ribbed, obtuse, shorter than or equaling culm, 1–5(–8) mm wide, glabrous or sparsely hirsute, sometimes scabrous on margins and veins abaxially. Inflorescences axillary and terminal, paniculate; panicles diffuse, 15–40(–80) mm, lateral clusters ± remote, the proximal pedunculate, peduncles often recurved or pendulous, filiform, compressed, (15–)20–100 mm; bracts subtending inflorescence leaflike, a bracteal leaf subtending panicles, usually 1/4–3/4 length of terminal internode, margins scabrous. Spikelets bisexual or unisexual; staminate spikelets 2–3 mm, pistillate spikelets 3–4(–5) mm; staminate scales lanceolate, pistillate scales ovate-lanceolate, acuminate. Achenes gray or brownish and/or with dark interangular lines and little pubescence, globose to ovoid, 1–3(–3.5) mm, reticulate to completely smooth, somewhat verrucose in some forms, reticulations smooth or pubescent with tufts of yellowish hairs, apex umbonate; hypogynium distinctly 3-lobed, lobes ovate-lanceolate, obtuse or subacute, sometimes cuspidate, appressed to base of achene.