The mandarin orange (Citrus reticulata), also known as the mandarin or mandarine, is a small citrus tree with fruit resembling other oranges, usually eaten plain or in fruit salads. Specifically reddish-orange mandarin cultivars can be marketed as tangerines, but this is not a botanical classification.
Mandarins are smaller and oblate, rather than spherical like the common oranges (which are a mandarin hybrid). The taste is considered less sour, as well as sweeter and stronger. A ripe mandarin is firm to slightly soft, heavy for its size, and pebbly-skinned. The peel is very thin, with very little bitter white mesocarp, so they are usually easier to peel and to split into segments. Hybrids generally have these traits to a lesser degree.
The mandarin orange 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 to a lesser extent the papedas and kumquat, were the ancestors of most other commercial citrus varieties, through breeding or natural hybridization; mandarins are therefore important as the only sweet fruit among the parental species. Though some mandarin cultivars remain pure, most have some degree of pomelo hybridization, while in some cases the amount of pomelo is substantial.
Citrus reticulata is a moderate-sized tree usually not exceeding 4 m (13 ft) in height; however, a 30-year-old tree can reach 5 metres (16 ft) (such a tree can yield some 5–7 thousand fruits). The tree generally has thorns.
The leaves are shiny and green, rather small. The petioles are short, almost wingless or slightly winged.
The flowers are borne singly or in small groups in the leaf-axils.