IRIS, the FLOWER-DE-LUCE, in botany, a genus of the triandria monogynia class. The corolla consists of six divisions, alternately reflected: the stigmata have the appearance of petals. There are twenty-two species, only two of which are natives of Britain, viz. the pseudacorus, or yellow flower-de-luce; and the fecitissima, or stinking gladden. The root is cathartic, and recommended in dropsies.