Scientific Name: Rorippa palustris spp. fernaldiana

Common Name: Fernald's yellowcress

Other Common Names: bog marshcress, bog yellowcress, common yellowcress, marsh yellowcress, marshcress, yellow watercress

Synonyms: Rorippa hispida, Rorippa islandica

Habit: 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: Leaves have 3-7 large lobes with toothed margins, stalks sometimes have lobes attached.

Identifying Characteristics: 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.

Seed Fruit: 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.

Where Found: 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.

  • Life cycle: biennial

  • Plant type: Herb

  • Plant family: Brassicaceae