Scientific NameRorippa palustris spp. fernaldiana
Other Common Names:
Synonyms (former Scientific Names):
Seedlings have 1-2 cm long, stalked, egg-shaped cotyledons. Mature plants have slender pale yellow taproots that give rise to a basal rosette of deeply lobed leaves. Several 30-80 cm upright flowering stems grow from the rosette.
Leaves have 3-7 large lobes with toothed margins, stalks sometimes have lobes attached.
No rhizomes, shallowly toothed leaves, yellow flowers.
Flower Seed Head
Clusters of yellow flowers on the ends of branches and in the up most leaf axils appear June through September. Flowers have 4 petals 1 to 2.5 mm long.
Cylindrical fruits with 2 chambers each containing several seeds curve upward to a point. Seeds are 0.6 mm long, yellow brown, and egg-shaped.
Found all over the United States. Marsh yellowcress prefers the wet, heavy, nutrient rich soils of poorly drained ditch banks, pastures, meadows. It is now being found in nursery and small vegetable crops.