Rorippa islandica is
a 35-50cm in height annual biennial herb occurring in paddies or
wetlands on roadsides. Radical leaves are 5-15cm long, pinnately
aperture, and the lobes coarsely cut themselves afresh. On-stem
leaves are shallowly cleft - each becomes the upper the shallower
upward, with bases expanding a little to embrace the stems in a
pair-of-ears way. Flowers are yellow, 3-4mm in diameter, and fruit
is 5-8mm in length. Bloom time: April-June.