Grafting is an artificial form of vegetative propagation in which parts of two young plants are joined together, first by artificial means and then by tissue regeneration. Typically, a twig or bud is cut from one plant and joined to a rooted plant of a related species or variety. The twig or bud is called the scion, and the plant onto which is it grafted (and that provides the roots) is called the stock. The scion eventually develops into an entire shoot system. Grafting often allows horticulturalists to combine the best features of two different plants into one plant. Sometimes the stock and scion retain independent characteristics, and sometimes the stock alters the characteristics of the scion in some desirable way.