Herbs, perennial, dioecious, caespitose, the base pubescent in the axils of glabrous cataphylls; cluster roots present. Culms unbranched below the inflorescence, erect, compressed, striate, without scabrid edges, glabrous. Sheaths persistent, appressed, scarious or membranous with an auriculate apex, the lamina broad, herbaceous becoming membranous; ligule area marked by a change in surface texture but not by a ridge or flap. Male and female inflorescences with spikelets at several or many nodes of slender inflorescence branches, erect or the males somewhat pendulous; the branches singly or in clusters at several upper nodes. Male spikelets with several flowers and many sterile lower glumes; female spikelets with 1 or several flowers; glumes blunt or acute. Male flowers: tepals 6, 2 outer tepals keeled, stamens 3, anthers not exserted. Female flowers: tepals 6, 2 outer tepals keeled, ovary 3-locular, style branches 3. Fruit a capsule. Seeds with irregular pattern of subangular or slightly lobed, flat or slightly convex, isodiametric cells. Culm anatomy: chlorenchyma of 2 or 3 layers of short peg cells; interrupted opposite outer vascular bundles by narrow, radially elongated sclerenchyma girders extending from parenchyma sheath to the epidermis; pillar cells absent; central cavity present.
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