Rhizomatous, perennials herbs. Rhizome
short, horizontally creeping, knotty. Leaves basal, 3-ranked; blades elongated
or reduced, ligules absent. Involucral bracts leaf like. Inflorescence
capitate. Spikes 1-few, sessile, cylindric, ellipsoid or globose, axil short.
Spikelets numerous, falling entire, crowded, bilaterally flattened. Glumes
several, 2-ranked, laterally flattened, sides membranous to hyaline, keel
strongly acute, sometimes winged, smooth, spinulate or serrulate. Flowers 1-5
per spikelet, bisexual or staminate in upper glumes. Perianth segments absent.
Stamens 2-3. Stigmas 2, style continuous with ovary. Nutlets 1-2 per spikelets,