Gymnocalycium mihanovichii, often called chin cactus, is a species of cactus from South America commonly grown as a houseplant. The most popular cultivars are varied mutants which completely lack chlorophyll, exposing the red, orange or yellow pigmentation. These cultivars are often called moon cactus. Since chlorophyll is necessary for photosynthesis, these mutations die as seedlings unless grafted onto another cactus with normal chlorophyll. (Wikipedia.com)
