Tangerines are a group of orange-coloured citrus fruit consisting of hybrids of mandarin orange with some pomelo contribution. The mandarin orange (Citrus reticulata), also known as the mandarin or mandarine, is a small citrus tree fruit. Treated as a distinct species of orange, it is usually eaten plain or in fruit salads.
Mandarins are smaller and oblate, unlike the spherical common oranges (which are a mandarin–pomelo hybrid). The taste is considered sweeter and stronger than the common orange. A ripe mandarin is firm to slightly soft, heavy for its size, and pebbly-skinned. The peel is thin, loose, with little white mesocarp, so they are usually easier to peel and to split into segments. Hybrids usually have these traits to a lesser degree. The mandarin is tender and is damaged easily by cold. It can be grown in tropical and subtropical areas.
According to genetic studies, the 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 (such as sweet and sour oranges, grapefruit, and many lemons and limes). The mandarin has also been hybridized with other citrus species, such as the desert lime and the kumquat. Though the ancestral mandarin was bitter, most commercial mandarin strains derive from hybridization with pomelo, which give them a sweet fruit.