Ludwigia leptocarpa (Nutt.) H.Hara

Robust hairy plants to 3 m tall, often somewhat woody below, reclining at base but erect and well-branched, with erect floating pneumatophores arising from roots under water. Leaves 3.5-18 x 1-4 cm, long-hairy, broadly lanceolate, narrowly cuneate at base, the apex acuminate; main veins on each side of midrib 11-20; petiole 0.2-3.5 cm long. Bracteoles at base of ovary absent or rarely present, narrowly deltate. Sepals 5, rarely 4, 6 or 7, 5.5-11 x 1.5-3 mm, deltate-acuminate, long-hairy, with a narrow wing running down from the sinus between adjacent sepals to the apical portion of the ovary. Petals 5-11 x 4-8 mm, obovate. Stamens twice as many as the sepals; filaments 2-4 mm long, the epipetalous ones shorter; anthers 1.2-1.6 mm long, extrorse and thus not shedding pollen directly on the stigma. Pollen shed in tetrads. Disk slightly elevated, the base of each epipetalous stamen surrounded by a depressed nectary densely covered with matted white hairs. Style 3-4.5 mm long, glabrous; stigma 2-2.5 mm across, c. 1 mm high, globose, the upper 2/3 receptive. Capsule 15-50 x 2.5-4 mm, relatively thin-walled, long-hairy, terete, dull light brown, with prominent ribs over the locules and less prominent ones over the septa, marked on the outside with bumps c. 0.5 mm apart, corresponding to the position of the seeds, slowly and irregularly loculicidal; pedicels 2-20 mm long. Seeds 1-1.2 mm long, uniseriate in each locule of the capsule, horizontal, shiny pale brown, finely pitted, obovoid; raphe much narrower than the body of the seed; each seed loosely embedded in an easily detached horseshoe-shaped segment of firm pale brown endocarp c. 1-1.5 mm thick and c. 1 mm high.

Found in wet soils, shallow water, sometimes submerged, in marshes, stream banks, wet fields or thickets, sometimes on sand bars along streams, at elevations up to 1,500 meters, though usually below 900 metres.

Can be grown by seedlings.