OMPHALEA, in botany: A genus of the triandria order, belonging to the monœcia class of plants; and in the natural method ranking with those of which the order is doubtful. The male calyx is tetraphyllous; there is no corolla; the receptacle, into which the antheræ are sunk, is ovate. The female calyx and corolla are as in the male; the stigma trifid; the capsule carnos and trilocular, with one seed.