Castor Bean (Ricinus communis)

Ricinus communis, commonly called the castor bean or castor oil plant, is the sole species in its genus, a fast growing shrub in the spurge family Euphorbiaceae that can reach about twelve meters in height but has no tolerance for cold. It is native to the southeastern Mediterranean basin, East Africa and India, and is now grown as an ornamental across temperate regions worldwide, recognizable by its large palmate leaves, which in some varieties are deep reddish purple maturing to green and in others remain purple brown throughout. Its spiny seed capsules hold large, mottled beans containing forty to sixty percent oil rich in ricinolein, but the same seeds also harbor ricin, a highly potent water soluble toxin that Guinness World Records has called the world most poisonous common plant, with as few as four to eight seeds a potentially lethal dose for an adult. Castor oil has been used since antiquity, fueling lamps in ancient Egypt and serving in traditional medicine across India, Rome and China, and today the crop, grown mostly in India, supplies industrial lubricants, biodiesel and cosmetic ingredients.