2n = 24

Submerged summer-green herb. Rhizome to 1 mm. diam., to 10 cm. long; internodes 1–2 cm. Stems much-branched, mostly < 1 mm. diam., to 100 cm. long; internodes 2–4 cm. long between apparent whorls of lvs. Lvs c. 2–5 cm. × < 1 mm., narrow-linear, 1-nerved, entire except for minute teeth near acuminate tip. Infl. within swollen lf-bases. Anther at first almost sessile, filament later 3–5 mm. long, reaching level of stigma; connective excurrent in knob of spongy tissue. Carpels us. 3–4; style at first longer than ovary, about as long as widely flaring, thinly membr., funnel-shaped stigma. Fr. 2.5 × < 1 mm., curved, shortly stipitate, yellow, surmounted by c. 1 mm. of style remnant.