Floating or prostrate in mud. Stems succulent, 1 to many, 4–25 in. long, rooting at nodes. Leaves pinnately divided; leaflets 3–7, oval to egg-shaped, entire to wavy-edged. Flowers small in terminal clusters, white. Seedpods spreading outward from stem or erect, 1/2 in. thin cylinder, straight to curving upward. Grows in slow-moving fresh water, marshes, edges of lakes, at elevations below treeline worldwide. Grown commercially for salad greens.
- Rarity: Common
- Flowering Time: All Year Long
- Life Cycle: Perennial
- Height: Floating
- Habitat: Bog/Fen/Wetland, Lake/Pond
- Found In: Olympic Np, Steens, East Gorge
- Native: Yes