An orange is a fruit of various citrus species in the family Rutaceae; it primarily refers to Citrus × sinensis. Oranges are rich in vitamin C and do not spoil easily. Orange flesh is 87% water, 12% carbohydrates, 1% protein, and contains negligible fat (see table). As a 100 gram reference amount, orange flesh provides 47 calories, and is a rich source of vitamin C.