in botany, a genus of the pentandria digynia clas. The fruit is somewhat oval, and striated; the involucrem consists of many leaves; and the petals are heart-shaped. There are 8 species, three of them natives of Britain, viz., the latifolium, or great water-parsnip; the nodiflorum, or creeping water-parsnip; and the erectum, or upright water-parsnip.