RUSCUS, BUTCHER'S-BROOM, in botany, a plant of the diccia syngenesia class. The calix of the male consists of six leaves; it has no corolla; the nectarium is central, oval, and perforated at the top: The calix, corolla, and nectarium of the female are the same with those of the male; it has one stylus; and the berry has three cells, and two seeds. There are five species, only one of them, viz. the aculeatus, knee-holly, or butcher's-broom, a native of Britain.