The fruit is a hesperidium, a specialised berry, globose to elongated, 4–30 cm (1.6–11.8 in) long and 4–20 cm (1.6–7.9 in) diameter, with a leathery rind or "peel" called a pericarp.
Apart from these core citrus species, there are Australian limes and the recently discovered Mangshanyegan. are now generally considered to belong within the citrus genus.
Trifoliate orange, which is often used as commercial rootstock, is an outgroup and may or may not be categorized as a citrus.
It has also been cultivated for the production and consumption of citrus juice.
Citrus plants are native to subtropical and tropical regions of Asia and the Malay Archipelago and they were first domesticated in these areas.
and it is in this region that some commercial species such as oranges, mandarins, and lemons originated.
Citrus fruit has been cultivated in an ever-widening area since ancient times.Important hybrids: Citrus × aurantiifolia – Key lime Citrus × aurantium – Bitter orange Citrus × latifolia – Persian lime Citrus × limon – Lemon Citrus × limonia – Rangpur Citrus × paradisi – Grapefruit Citrus × sinensis – Sweet orange Citrus × tangerina – Tangerine See also below for other species and hybrids.Citrus is a genus of flowering trees and shrubs in the rue family, Rutaceae.These estimates are made using genetic mapping of plant chloroplasts.Within the last few thousand years, all common citrus fruits (sweet oranges, lemons, grapefruit, limes, and so on) were created by crossing those original species.Citrus trees hybridise very readily – depending on the pollen source, plants grown from a Persian lime's seeds can produce fruit similar to grapefruit.