Soft aquatic or semi-aquatic herb, the creeping and rooting stems giving off ∞, erect, us. simple, branches 2-10 cm. tall. Lvs opp. linear, entire, subacute, 5-10 mm. long. Fls solitary in the axils of upper lvs, each subtended by 2 subulate, minutely serrulate bracteoles, unisexual; ♀ lower, sepals present but very small, petals and stamens 0; ovary c. 1 mm. long, styles 4, divergent, stigmas plumose; ♂ uppermost, the undeveloped ovary forming a short pedicel; sepals 4, 1 mm. long, narrow-oblong; petals 4, reddish, c. 2 mm. long, becoming reflexed; stamens 8, filaments elongating; fr. partly reddish, c. 1·2 mm. long, narrowed above, surface finely striate.

Perennial mat-forming herb; stems green, erect or prostrate, 2-10-(15) cm long, not branched or sparingly so at base. Lvs monomorphic, entire, linear, 2-6 × 0.5 mm, decussate. Upper lvs indistinguishable from other lvs. Fls unisexual, ♂ and ♀ often borne on separate stems, or ♂ borne in upper axils with ♀ below. Bracteoles deltoid, 0.6-0.7-(1.3) × 0.2-0.3 mm. ♂ fls sessile or on pedicels up to 1 cm long; sepals 4, 0.9-1.4 × 0.3-0.5 mm; petals 4, 1.3-1.7-(2.5) × c. 0.8 mm, oblanceolate or narrowly obovate, red, hooded. ♀ fls with pedicels 0.2-0.5-(1.0) mm long; petals 0. Frs ovoid or nearly so, 1.0-1.5 × 1.1-1.2 mm, deeply channelled opposite sepals, smooth to weakly striated, not verrucose.