CIRCEA, or ENCHANTERS NIGHTSHADE, in botany, a genus of the diandria-monogynia class. The corolla consists of two petals; the corolla has likewise two leaves; and the capsule contains but one seed. The species are three, two of which are natives of Britain, viz. the lutiiana, or enchanters-nightshade; and the alpina, or mountain enchanters-nightshade.