Ricinus communis, the castor bean or castor oil plant, is a species of perennial flowering plant in the spurge family, Euphorbiaceae. It is the sole species in the monotypic genus, Ricinus, and subtribe, Ricininae. Its seed is the castor bean, which despite the term is not a bean (as it is not the seed of a member of the family Fabaceae). Castor is indigenous to the southeastern Mediterranean Basin, East Africa, and India, but is widespread throughout tropical regions (and widely grown elsewhere as an ornamental plant). Castor seed is the source of castor oil, which has a wide variety of uses. The seeds contain 40–60% oil that is rich in triglycerides, mainly ricinolein. The seed also contains ricin, a highly potent water-soluble toxin.

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