: a tropical Old World herb of the genus Ricinus (R. communis) widely grown as an ornamental or for its oil-rich castor beans that are a source of castor oil
Castor-oil plant (Ricinus communis).—Kenneth and Brenda Formanek/EB Inc.
Large plant (Ricinus communis) of the spurge family, probably native to Africa and naturalized throughout the tropics. It is grown commercially for the pharmaceutical and industrial uses of its oil and for use in landscape gardening because of its handsome, giant, fanlike leaves. The bristly, spined, bronze-to-red clusters of fruits are attractive but are often removed before they mature because of the poison concentrated in their mottled, beanlike seeds. There are hundreds of natural forms and many horticultural varieties of this species.