Rorippa palustris

Annual or biennial, to 60 cm high (rarely more), erect; stems often red-pigmented, glabrous. Leaves 2–12 cm long, glabrous or hairy, lobes irregularly serrate, margins toothed; basal leaves petiolate, auriculate at base, deeply incised with large terminal lamina; stem leaves similar, becoming smaller and sometimes simple. Sepals c. 1.5 mm long; petals 1–2 mm long, yellow; stamens 6. Fruit spreading to horizontal, oblong to ellipsoid, curved, 4–9 mm long (excluding style), 2–3 mm wide, contracting abruptly to style; style 0.5–1 mm long; pedicels spreading to horizontal, 4–6 mm long, glabrous or sparsely hairy; seeds in 2 rows per locule, coat covered with small bumps. Flowers mostly spring–summer.