Perennial, 60-100 cm. Rhizome creeping, black, bearing tubercles. Sterile stems
about 1 cm. in diam., branching, 20-40-ridged, white, their sheaths 1.5-3 cm, ending in subulate teeth of same number as ridges; lateral branches numerous, spreading to erect, simple, thin, 4-5-angled, green, with short 4-toothed sheaths; fertile stems 20-40 cm, simple, hollow, pale brown; sheaths close together, with about 30 subulate teeth. Spike 5-15 x 1-2 cm. April-July.