The term "succulent" refers to a wide variety of plants -- those that are particularly adept at storing water within their flesh. While the word is commonly associated with the cactus, not all succulents are members of the cacti family. Even trees in harsh, arid climates can be succulents.
Other succulents include the jade plant (Crassula arborescens), the snake plant (Sansevieria trifasciata), the medicine plant (Aloe barbadensis), the century plant (Agave Americana) and the flowering Kalanchoes (Kalanchoe blossfeldiana), reports the University of Minnesota Extension service. "Coevolution" is the term that describes a number of disparate plants adopting the same strategy for survival.
Succulents conserve water by limiting the size of their plant bodies, including the reduction of branches and leaves. When leaves do exist, they typically are coated with a white, waxy substance that reflects sunlight to keep the flesh of the plant cool and minimize water loss through transpiration.