Potamogeton octandrus Poir.

Herb, 20-100 cm high, from a creeping rhizome. Stipular sheaths small, convolute, soon decaying. Leaves dimorphic: submerged leaves 30-70 × 1-3 mm, linear to narrowly linear-lanceolate, alternate, translucent; apex acute or acuminate; the area between midrib and lateral nerves consisting of lacunar tissue; floating leaves up to 20 × 5 mm, lanceolate to oblong-lanceolate, with a petiole 1 cm, opposite, just below the flower spikes, not translucent, apple-green. Spikes longer than leaves; flowers usually 2 per whorl, with 3-7 whorls per spike. Drupe 2 mm, rounded to oblong in outline, tapering to base; beak relatively long, upturned.

Widespread in tropical Africa, Gauteng and KwaZulu-Natal, South Africa, Madagascar, South and East Asia, New Guinea and Australia.