Citrus reticulata

A mandarin orange (Citrus reticulata), often simply called mandarin, is a small, rounded citrus tree fruit. Treated as a distinct species of orange, it is usually eaten plain or in fruit salads. The mandarin is small and oblate, unlike the roughly spherical sweet orange (which is a mandarin-pomelo hybrid). The taste is sweeter and stronger than the common orange. A ripe mandarin orange is firm to slightly soft, heavy for its size, and pebbly-skinned. The peel is thin and loose, with little white mesocarp, so they are usually easier to peel and to split into segments. Hybrids have these traits to lesser degrees. The mandarin orange is tender and is damaged easily by cold. It can be grown in tropical and subtropical areas.

According to genetic studies, the wild mandarin was one of the original citrus species; through breeding or natural hybridization, it is the ancestor of many hybrid citrus cultivars. With the citron and pomelo, it is the ancestor of the most commercially important hybrids. Though the ancestral mandarin orange was bitter, most commercial mandarin strains derive from hybridization with the pomelo, which gives them sweet fruit.