The Mandarin orange, also known as the mandarin or mandarine (both lower-case), is a small citrus tree (Citrus reticulata) with fruit resembling other oranges. Mandarin oranges are usually eaten plain or in fruit salads. Specifically reddish-orange mandarin cultivars can be marketed as tangerines, but this is not a botanical classification. When exporting began, local Mandarin oranges were named after their port of origin.
The tree is more drought-tolerant than the fruit. The mandarin is tender and is damaged easily by cold. It can be grown in tropical and subtropical areas.
According to molecular studies, the mandarin, the citron, the pomelo, and the papeda were the ancestors of all other citrus species and their varieties, through breeding or natural hybridization; mandarins are therefore all the more important as the only sweet fruit among the parental species.