Perennial herb, up to 500 mm tall, rhizomatous. Leaf sheaths closely convolute. Male and female inflorescences similar; inflorescence dark brown. Spikelets with more than 4 flowers, 8-15 mm long.
Perennial herb, up to 0.6 m high, rhizomatous, dioecious. Leaf sheaths acute-acuminate. Flowers: male and female inflorescences similar; spikelets several-flowered, 8-15 mm long, slender, spindle-shaped; florets hidden by hard, brown, glossy, overlapping bracts with protruding anthers or 2 style branches; Nov.-Jul. Fruit a capsule.