» For the vegetable sometimes called Chinese watercress, see Ipomoea aquatica. Watercresses (Nasturtium officinale, N. microphyllum; formerly Rorippa nasturtium-aquaticum, R. microphylla) are fast-growing, aquatic or semi-aquatic, perennial plants native from Europe to central Asia, and one of the oldest known leaf vegetables consumed by human beings. It's an invasive species in the Great Lakes region where it was first sighted in 1847. These plants are members of the Family Brassicaceae or cab… (More on Watercress)