Citrus paradisi occurred spontaneously in the West Indies. Ruby Red arose in McAllen, Texas in 1929 and is propagated vegetatively. Fortunella and Aegle also eaten and from the same family. They were widely distributed when Colombus came. They are multiple fruits.
Most modern cultivars are parthenocarpic.
They set seed without fertilization. Reproduced vegetatively normally. They were taken to many countries by the Portugese, Spanish, and Dutch. They were taken to Hawaii by the Doles. They have long been an important food plant.