Rorippa palustris (L.) Besser
Perennial, rarely annual, taprooted herb. Stems erect, rarely decumbent, glabrous or hairy, (3)-20-40-(100) cm tall. Lvs glabrous or hairy; margins toothed. Rosette lvs petiolate, auriculate at base, deeply pinnatifid to pinnate, (2)-4-7-(10) × 1-3 cm. Stem lvs similar to rosette lvs, auriculate at base, becoming smaller with narrower lobes above, the uppermost sometimes simple. Pedicels glabrous or sparsely hispid, erecto-patent at flowering, spreading at fruiting, (2)-4-7 mm long. Sepals 1.5-2-(2.5) mm long. Petals yellow, = sepals. Silicle glabrous, oblong to elliptic, curved, (2)-4-7 × 2-3 mm; valves not veined; style 0.5-1 mm long. Seeds pale brown, c. 0.8 mm long, finely colliculate, in 2 rows per locule.
N.; S.: throughout.
Also indigenous to N. temperate regions
Lowland to montane wet places, especially tarns, streams, bogs, lagoons.
FL (Oct)-Dec-Jan-(Feb) (Oct)- Jan-Feb-(May).
This sp. has probably been introduced to N.Z., but it is almost certainly a native plant as well (Garnock-Jones, op. cit.). It was treated by Allan (1961) as Rorippa islandica.