Cycnogeton lineare Sond.

Slender perennial aquatic herb. Rhizome woody, fibre-covered, 6–13 mm thick. Tubers ± ellipsoid or globular to obovoid, 9–28 mm long, 6–11 mm diam. Leaves ± linear, apparently submerged or floating, 23–73.5 cm long, 1.5–5 (–10) mm wide, possibly somewhat spongy basally; basal sheath tapered; T.S. not known. Scape at fruiting c. 15–45 cm long, 1–4.5 mm diam. Infructescence a raceme, 3.5–14.5 cm long, 7–17 mm diam.; pedicels 1–3.5 mm long. Fruits 10–47 per infructescence, ellipsoid to ellipsoid-obloid, 6.5–9.6 mm long, 4.1–6.1 mm diam. Carpels 6, normally all maturing; central axis absent; mature carpels attached along (27%–) 46%–72% of their length, straight or sometimes twisted around each other apically, with 1 dorsal and 2 lateral inconspicuous to prominent rounded ridges.

Occurs in usually still and ephemeral fresh water to 40 cm deep, in swamps, ditches and low lying floodland, occasionally in small creeks and pools, rarely in brackish water. 

Plants can be grown from seed.