Perennial tufted herb to 70 cm. high. Stems usually erect, leafy, sometimes trailing and then rooting and branching at the nodes. Cataphylls 1–2, up to 5 cm. long, often tinged reddish, with membranous margins; apex sometimes crowned with a rudimentary leaf. Leaves 2–5 to a stem, cylindrical, septate, up to 25 cm. long; sheaths open, up to 7.5 cm. long, biauriculate, margins membranous; auricles 1–2.5 mm. long. Inflorescence taller than the leaves, branched, consisting of up to 20 subspherical capitula each with 20 or more flowers; branching sometimes condensed and the inflorescence appearing to consist of only 2–3 large capitula; branches from a few mm. up to 8 cm. long in each inflorescence; lower bracts leaf-like, 2–5 cm. long; upper bracts lanceolate, about 5 mm. long, apiculate, scarious; flowers subsessile, each subtended by a single bract; bracts triangular, 2–2.5 mm. long, acute, membranous. Perianth-segments equal, lanceolate, 3.5–4.5 mm. long, 1.25 mm. wide, acute, margins membranous, green when young, becoming reddish-brown. Stamens 3, sometimes 6; filaments linear, 1.25 mm. long; anthers linear, 0.75 mm. long. Ovary 1-celled; style very short; stigmas 1.25 mm. long. Capsule trigonous, oblong, 2.5–3.5 mm. long, apex drawn out and apiculate, shiny, buff-coloured below, red-brown to almost black above. Seeds ovoid, 0.5 mm. long, apiculate, reticulated, red-brown. Fig. 1/8–10.
