Flora of New Zealand Series

Perennial herb; stems weak, slender, (5)-10-25-(40) cm long, prostrate or erect, usually simple. Lvs usually distinctly dimorphic, sometimes monomorphic. Submerged lvs in whorls of 3-4-(5), ovate to orbicular, (6)-10-20-(25) × 10-16-(25) mm, pectinate; pinnae 10-22, filiform, 5-6-(20) mm long. Aerial lvs in whorls of (2)-3-4-(5), linear, (2)-5-7-(12) × 0.5-1-(1.5) mm, usually flattened but occasionally terete to filiform; margin entire or sometimes weakly toothed. Fls unisexual, ♂ in upper 1-8 whorls, ♀ in lower 2-6 whorls, with usually 1-2 sterile whorls between, occasionally all whorls ♀. Bracteoles ovate, (0.4)-0.5-0.8 × (0.2)-0.4-0.5 mm. ♂ fls sessile or nearly so; sepals 4, ovate, 0.4-0.6 × 0.3-0.4 mm; petals 4, hooded, 1.8-2.7-(3) × c. 1.4 mm. ♀ fls sessile; sepals and petals 0. Frs 0.8-1.1 × 0.8-1 mm, pale yellow-brown or greenish, ± cylindric, smooth apart from scattering of very small tubercles on outer face of mericarps.

N.; S.; St.; Ch.

Probably also indigenous to Tasmania.

Lowland and submontane, usually in or near still or slowly moving water.