HYDROCOTYLE, WATER-NAVELWORT; a genus of the digynia order, belonging to the petandria class of plants. There are several species, none of which are ever cultivated in gardens. One of them, a native of Britain, growing in marshy grounds, is supposed by the farmers to occasion the rot in sheep. The leaves have central leaf-stalks, with about five flowers in a bundle; the petals are of a reddish white.