Aquatic or semi-aquatic perennial herb from a fibrous root; stems leafy, succulent, submersed or partly floating, sometimes prostrate on mud, 10-60 cm long, only the tip usually erect, rooting at the nodes, glabrous or sparsely hairy.
Basal leaves pinnate with 3-7 leaflets, egg-shaped to broadly oblong, unstalked, without ear-like lobes at the bases, entire or wavy-margined, terminal leaflets larger than lateral, stalked, base of the stalks usually with small ear-like lobes at the bases, glabrous; stem leaves similar.
Racemes corymbose, elongate in fruit; flower stalks 6-20 mm long, spreading or even slightly recurved to ascending; petals white to purplish-tinged, 3-4 mm long, broadly spoon-shaped; sepals 2.5-3.5 mm long, glabrous, the outer pair pouched at base.
Siliques, widely spreading to somewhat ascending, slightly curved upward to straight, narrowly oblong, 10-25 mm long, 2-3 mm wide; beaks obscure, rarely to 0.5 mm long; seeds distinctly 2-rowed, flattened and very slightly wing-margined, coarsely wrinkled, about 1 mm long, about 24-60 pits per side.
Source: The Illustrated Flora of British Columbia