Callitriche stagnalis Scop.

Amphibious monoecious herb. Aquatic stems to c. 1 m long, often forming dense mats in water or on mud. Submerged lvs not markedly different from rosette or floating lvs, 4–10–(25) × 2–4–(6) mm, linear-spathulate, spathulate or obovate, but never linear, 3-, 5-, or 7-nerved; free veins 0; apex rounded or slightly emarginate; rosette lvs to 10 × 6 mm, broad-elliptic to suborbicular, entire; terrestrial lvs usually smaller and rarely > 5 × 3 mm. Fls in axils of rosette lvs, solitary or 1 ♂ and 1 ♀ together. Bracteoles white, falcate, persistent. Filaments c. 2 mm long; anthers c. 0.2 mm long. Styles 2–3.5 mm long, persistent and recurving at fruiting. Fr. subsessile, 1.2–1.7 mm diam., orbicular, pale; mericarp faces ± flat; wing rather narrow, usually extending round the mericarp; commissural groove wide, deep, tapering towards the top.

[From: Webb et al. (1988) Flora of New Zealand. Volume 4.]

Flowering: Dec.–Feb.