Rhizomes branched, rooting at nodes. Leaves 2-7 together on short erect shoots, flattened, linear, 7-17-veined, margin entire or dentate; sheaths auriculate, ligulate. Flowers solitary and terminal. Perianth absent. Male flowers pedunculate; anthers 2; pollen filiform. Female flowers sessile or subsessile; styles divided into 2 filiform stigmas. Fruitlets laterally subcompressed, with bony pericarp, beaked.
Rhizome creeping, monopodial, with many vascular bundles; each node with 1– 5 branched roots and a short erect stem bearing 2– 7 leaves; scales ovate, scarious
Leaves with the sheath compressed, bi-auriculate, ligulate, persisting longer than the blade, leaving a scar when shed and giving the stem an annular appearance; blade linear, margins entire but for the distal part which becomes serrulate or spinulose, apex ± toothed; nerves 7– 17, with perpendicular cross-veins
Flowers solitary and terminal, enclosed in a leaf similar to others, a bud in the axil of the penultimate leaf lengthening to give rise to a sympodium
Fruit with stony pericarp, laterally compressed, semi-circular to elliptic in outline, with dorsal ridges and a beak.
Pistillate flowers sessile or shortly stalked, of 2 free ovaries each with a short style, distally bifid
Staminate flowers stalked, of 2 dorsally connate anthers, attached at the same height, each crowned by subulate tip