Mainly found about Upper and Lower Lough Erne, Lough Neagh and its tributaries, the Upper and Lower River Bann and the River Lagan, but with some other scattered localities. On riversides, lakesides, in ditches, ponds and marshes.
A native perennial with undivided leaves and small yellow flowers.
All names: Rorippa amphibia (L.) Besser; Radicula amphibia (L.) Druce; Nasturtium amphibium (L.) R.Br.; Armoracia amphibia (L.) G.F.W.Mey.