VISCUM, in botany: a genus of plants of the class diadelphia, order tetrandria, and in the natural system arranged under the 48th order, aggregata. The male calyx is quadripartite; the antheræ adhere to the calyx; the female calyx consists of four leaves; there is no style; the stigma is obtuse. There is no corolla; the fruit is a berry with one seed. There are 9 species; only one of which is a native of Britain, viz. the alburn, or common mistletoe. It is a shrub growing on the bark of several trees: the leaves are conjugate and elliptical, the stem forked; the flowers whitish in the axle of the leaves. This plant was reckoned sacred among the Druids.