In Ethiopia and Eritrea, wild castor plants have been preserved to this day. In the northern part of the Red Sea coast of North Africa and along the Atlantic and Mediterranean coasts, small-fruited wild castor beans are widely distributed. On the coastal beaches and light-colored soil, you can see patches of castor bushes. According to Nigel and Gale, castor extends to the hinterland of the African continent. In Yemen, Ba Bouhour Man Strait, wild castor shrubs also occupy a huge area. On the Indian Ocean coast of Africa, there is another wild castor with bigger seeds.
Also in Africa, castor was introduced for cultivation. Throughout central and northern Africa, domesticated castor can be seen, which is usually used as a fence or shelter belt around tobacco, cotton and sweet potato plantations.
Ricinus communis was first introduced to Africa, and then spread to other places outside its origin. The cultivated castor was introduced to ancient Asia. Soon, castor spread from Asia to America, and then to Europe.
After being introduced to Mexico, Guatemala and other tropical areas in America, castor in Africa is in the wild again. Its bushes soon occupied a huge area.
In the southern United States, as in many other tropical areas, not only can wild castor be seen, but it is also often a weed in field crops. Ricinus communis, like marijuana, is scattered on both sides of roads and ditches, in front of houses and fields.
Ricinus communis is also widely distributed in Central Asia, India and Afghanistan. According to the existing ways to form the types of cultivated castor, it can be concluded that wild castor is the offspring of cultivated castor in ancient times, and it has transitioned to the weed stage and become a cultivated plant again. At first, most of them were planted beside the courtyard and around the road in Dachuan.
Castor, now cultivated as an ornamental plant, is very similar to African castor, far beyond its original natural distribution area, and has arrived in Scotland. In such a vast field, the cultivated African castor (horticulture in Otawa) also differentiates like wild plants and weeds. Under the influence of cultivation and long-term selection, many types or varieties of castor have been formed.