All citrus trees belong to the single genus Citrus and remain almost entirely interfertile. Different names have been given to the many varieties of the species. Italy for its peel, producing tarocco blood orange primary essence for perfumes, also used to flavor Earl Grey tea. It is a hybrid of bitter orange x lemon.
Like the sweet orange, it is a pomelo x mandarin hybrid, but arose from a distinct hybridization event. It often serves as a rootstock for sweet orange trees and other Citrus cultivars. An enormous number of cultivars have, like the sweet orange, a mix of pomelo and mandarin ancestry. The French word, in turn, comes from Old Provençal auranja, based on Arabic nāranj. The sweet orange is not a wild fruit, having arisen in domestication from a cross between a non-pure mandarin orange and a hybrid pomelo that had a substantial mandarin component. In Europe, the Moors introduced the orange to the Iberian Peninsula which was known as Al-Andalus, with large scale cultivation starting in the 10th century as evidenced by complex irrigation techniques specifically adapted to support orange orchards. Spanish travelers introduced the sweet orange into the American continent.
