Rorippa palustris var. palustris is an annual or biennial herb, taprooted, erect, to 40 cm tall, branched.
Leaves alternate, narrow, pinnately divided, stem leaves winged near base, with small, ear-shaped lobes.
Flowers yellow, 4-parted, about 0.3 cm wide, petals about as long as sepals; blooming May-Aug.
Fruit a capsule oblong-cylindrical ca 0.5 cm long, with a small blunt beak, seeds in two rows on each side; fruiting July-Oct.
Wetland status: OBL.
Frequency in NYC: infrequent.
Habitat: Moist to wet open areas. Sometimes a lawn weed in moist soil.