2n = 12

Submerged summer-green herb. Rhizome to 1 mm. diam., internodes 1–2 cm. long. Stems occ. branched, to 20 cm. long, filiform; internodes c. 1–4 cm. long. Lvs regularly alt.; lf-base at first sheathing stem, to 4 mm. long, fibrous in age; lamina c. 2.5–3.5 cm. × 1 mm., 1-(or 3-) nerved, entire, tip squarely truncate, nerve (or nerves) shortly excurrent. Fl. enclosed within lf-bases. ♂ on pedicel that elongates to 5 mm.; per.-segs mucronate, enclosing only extreme base of anther; stamen solitary; anther 2 × 0.6 mm., sessile, curved; pollen sacs 2, connective excurrent in short, sharp mucro. ♀ shortly pedicellate; per.-segs narrow-oblong, ± laciniate, c. 1.5 × 0.5 mm.; carpels us. 3, occ. 4, shortly stipitate; style narrower than ovary, stigma obliquely funnel-shaped with long-fimbriate margins. Achene c. 1.5–2 × 0.5 mm., asymmetrically oblong, yellow, smooth, narrowing above to style-remnant c. 1 mm. long. 2n = 12.