Potamogeton octandrus Poir.

Aquatic herb; stem filiform, branched, submerged, 0.5 mm broad. Submerged leaves sessile, narrowly linear, filiform, less than 3 mm broad with a well-marked lacunar band bordering the midrib; floating leaves 2-3.5 cm long, 6-7 (-10) mm broad, 5-7-nerved, ovate-lanceolate, long-petioled; petioles 1-2 (-2.5) cm long. Stipules free, open lanceolate-ovate, up to c. 1.2 cm long, 2-3.5 mm broad, membranous, caducous. Spikes few-flowered, globose, 1-1.5 cm long. Fruitlets obovoid, c. 1.5 mm long and almost equally broad, conspicuously beaked, often ornamented basally.

Tropical Africa, Asia and Australia.

Distribution: A very distinct species, widely distributed in tropical and N.E. South Africa, Madagascar, S.E. Asia and N.E. Australia.

700-1000 m

Fl.Per.: July-August.

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.

Potamogeton octandrus is an aquatic plant species in the genus Potamogeton. It is found in slow-moving fresh water. The specific epithet means 'eight-stamened'.