The Watercress (Nasturtium officinale) belongs to Brassicaceae (the Mustard family). It is a perennial herb that is native to Europe. This herb was introduced into Japan in the early Meiji Era (1868-1912) and naturalized in so many places nowadays. The stems are succulent and creeping on the ground, they can be taking roots at the nodes easily. The umbellars are borne and bloom white flowers from May to October. The young shoots have a brisk scent and hot flavor, and used for a garnish of steak or hamburger.
It has been called "Oranda-garashi" (Dutch mustard) or "Seiyo-zeri" (Western parsley) in Japanese, but the Ministry of Agriculture, Forestry and Fisheries has adopted the French word "Cresson" as the unified name.