The rubber tree is a member of the Ficus family, Ficus elastica. The Ficus elastica, sometimes called the India rubber tree, is native to South America. However, current natural rubber cultivation is primarily in the area around India and Malaysia. It is one of the oldest plants to be cultivated as a houseplant.
Commercial rubber trees originated in Brazil, which played a major role in natural rubber production for many years. Rubber trees were introduced into Sri Lanka in 1877 when 22 seedlings were transferred from Singapore to the island. By 1900, commercial rubber plantation practices became well-established, and south and southeast Asia became the center of natural rubber production.
Natural rubber is made by collecting the sap from the rubber tree and heating it over a fire. As the sap is heated, the proteins are destroyed, leaving natural hard rubber. This product is often called either Technically Specific Rubber (TSR) or Sheet Rubber.
The liquid from the rubber tree that contains latex lies below the layer that contains the tree sap used for hard rubber. To make latex, the tree is tapped a second time below the sap layer. Instead of being heated, the raw latex is spun in a centrifuge until it contains about 60 percent latex rubber compounds and 40 percent other natural compounds.
Most commercial rubber tree cultivation occurs in Thailand, Indonesia, Malaysia and Sri Lanka. Rubber trees will grow in any hot, humid tropical climate, but commercial cultivation in areas outside of these four countries has dropped off. Latex is also produced in these same areas, but only about 10 percent of the production is natural latex.
Although true rubber trees make good houseplants, a number of other species are often sold as rubber tree houseplants. These species are: Ficus vogelii, Ficus altissima, Ficus lyrata, Ficus religiosa and Ficus rubiginosa. Although these varieties can look very much like a rubber tree, they often don't naturally grow as tall as a true rubber tree, which can grow up to 40 feet tall. They also don't produce sap that is suitable for making rubber.