Rhizomatous aquatic. Leaves floating, small, elliptic to lanceolate. Flowers distichous, white, with 2 tepals, stamens usually 6.
Tubers globose, 2 cm in diam., brown. Leaves: primary rarely developed, submerged, filiform to linear, with a wavy margin, tapered above and below; later leaves petioled and with a floating lamina, narrowly lanceolate to oblong, c. 5 cm long and 1 cm broad, apex acute, base rounded to attenuate, lateral nerves indistinct, margin slightly prominent. Spikes bifid, compact at first, lengthening during anthesis, in fruit up to 2 cm long, laxly 4-8-flowered. Flowers scentless, situated dorsally on the rhachis; perianth-segments 2, white with a pinkish tinge below, oblong-lanceolate, 5-10 mm long, accrescent in fruit. Stamens usually 6, filaments subulate, 2-4 mm long, anthers black. Carpels 2-4, ovules 2. Follicles narrow-ovoid, green, membranous, 8 mm long, with a straight beak; seeds 7 mm long, with a thin spongy outer covering.