botany, a genus of the monocotyledonous family. The calyx of the male consists of three segments, and the corolla of three petals; and the stamens are about 24. The calyx and corolla of the female are the same with those of the male; it has no pistil; and the seeds are many, and naked. The species are four, only one of them, viz. the sagittifolia, or arrow head, a native of Britain.