Botanical name: Rorippa palustris Family: Brassicaceae (Mustard family)
Synonyms: Sisymbrium amphibium var. palustre, Rorippa islandica
Marsh Yellow Cress is a biennial or annual plant is 1-3 ft tall. It is normally erect and branches occasionally. Stems are light green to reddish green, hairless, and strongly furrowed or ribbed. Alternately arranged leaves are up to 7 inches long and 2 inches across, becoming smaller above. The rather variable leaves are oblanceolate or oblong-ovate, hairless, pinnately lobed, and toothed. Often, there are 1-2 pairs of moderately deep lobes near the base of each leaf, and shallow lobes or large teeth elsewhere. The lower leaves have stout petioles, while the upper leaves are usually stalkless. The upper stems terminate in racemes of flowers about 4-12 inches long. The small flowers bloom at the tip of each raceme, while the cylindrical seedpods develop below. Each flower is about 3-5 mm across, consisting of 4 yellow petals, 4 greenish yellow sepals, several stamens with yellow or light brown anthers, and a pistil with a stout style. Marsh Yellow Cress spreads by reseeding itself.
Identification credit: Gurcharan Singh
The flower labeled Marsh Yellow Cress is ...