hardy perennial European herb ( Nasturtium officinale ) of the family Cruciferae ( mustard family), widely naturalized in North America, found in or around water. Often cultivated commercially for the small, pungent leaflets, it is used as a peppery salad green or garnish. Other plants of the genus are sometimes called watercress and are used similarly. Watercress was formerly used as a domestic remedy and against scurvy. www.encyclopedia.com Watercress contains significant amounts of iron, calcium and folic acid, in addition to vitamins A and C. In some regions watercress is regarded as a weed, in other regions as an aquatic vegetable or herb. Where watercress is grown in the presence of animal waste, it can be a haven for parasites such as the liver fluke Fasciola hepatica. Many benefits from eating watercress are claimed, such as that it acts as a mild stimulant, a source of phytochemicals and antioxidants, a diuretic, an expectorant, and a digestive aid.