ISCHÆMUM, in botany: A genus of the monocæcia order, belonging to the polygamia class of plants; and in the natural method ranking under the 4th order, Gramina. The calyx of the hermaphrodite is a biflorous glume; the corolla bivalved; there are three stamens, two styles, and one seed. The calyx and corolla of the male as in the former with three stamens.