(δια "twice," and ἄδειος "a brother"), clasps the 17th in the sexual system, comprehending those plants which bear hermaphrodite flowers with two sets of united stamens; but this circumstance must not be absolutely depended on. They are the papilionaceae of Tournefort, the irregulares tetrapetali of Rivinus, and the leguminosa of Ray. See Botany, the Scheme, p. 439, and Plate CII, fig. 17.