the toothache-tree, in botany; a genus of plants of the clas of diccia, and order of pentandria; and in the natural system arranged under the 46th order, Hederaceae. The talyx is quinquepartite; there is no corolla; the female flower has five pistils and as many monospermous capsules. There are two species, the clava herculis, and the trifoliolatum; neither of which are natives of Britain.