Densely tufted, us. reddish. Culms rooted at the base, the rest floating, up to 60 cm. long, c. 0.5 mm. diam., flaccid, lfy, much branched. Lvs (2)–6–10 cm. long, distant or tufted, filiform, flaccid, margins slightly scabrid towards lf-tip; sheath very long, green or red-brown, margins membr., produced at the tip to form a ligule. Spikelets 7–12 mm. long, 2–4-fld, narrow-linear, solitary, terminal, subtended by a glume-like bract, or rarely 2–3 spikelets distant at the end of the culm, the lower ones subtended by more lf-like bracts. Glumes 3–4, lanceolate, obtuse, membr., light red or pale cream; all fertile or the lowermost empty. Hypog. bristles 0. Stamens 3. Style-branches 3. Nut c. 2 × 1 mm., obovoid, brown with black patches or entirely black.