Botanical Descriptions of Castor Bean

Abstract

Castor bean, Ricinus communis L., belongs to the spurge family (Euphorbiaceae). Despite its name, the seed is really not a true bean and it is not related to the bean or legume family Fabaceae. It is an oilseed crop cultivated mainly in India, Mozambique, Brazil, and China; and believed to have polyphyletic origin with four centers of diversity. The plant is an annual herb, or a perennial shrub or small tree. Blooms are found on the stem and certain other parts of the castor bean plant. The inflorescence is an erect and terminal panicle of cymes (panicled cymes). The flowers are usually unisexual and monoecious. The staminate and pistillate flowers are borne on the same inflorescence. Castor bean has a mixed mating system generating both selfed and cross-fertilized offspring. It is basically a long-day plant, but is adaptable, with less yields, to a wide range of photoperiods. The fruit is botanically a ``schizocarpic capsule{''} or regma. The seed is ovoid, tick-like, carunculate, albuminous, poisonous, and allergenic. The germination is epigeal. The oil extracted from the seeds is non-drying in nature with a lot of uses in medicine, cosmetics, biodiesel, and other industries. The detoxified castor bean meal and husk are used as animal feed. The castor bean meal is also an organic manure. The active poison in castor bean seeds is ricin, a very deadly protein called lectin. Ricin is found in the meal or cake after the oil has been extracted. It is not carried over into the oil if it is properly extracted, but remains in the meal. The leaves contain ricin, but in much smaller quantities than in the seeds.