Persian orange

The Persian orange, grown widely in southern Europe after its introduction to Italy in the 11th century, was bitter. Sweet oranges brought to Europe in the 15th century from India by Portuguese traders, quickly displaced the bitter, and are now the most common  variety of orange cultivated. The sweet orange will grow to different  sizes and colours according to local conditions, most commonly with ten carpels, or segments, inside.

Some South East Indo-European tongues name orange after Portugal, which was formerly the main source of imports of sweet oranges. Examples are Bulgarian portokal, Greek portokali , Persian porteghal , and Romanian portocala. Also in South Italian dialects , orange is named portogallo or purtualle, literally "the Portuguese ones". Related names can also be found in other languages: Turkish Portakal, Arabic al-burtuqal, Amharic birtukan, and Georgian phortokhali.

Portuguese, Spanish, Arab, and Dutch sailors planted citrus trees along trade routes to prevent scurvy. On his second voyage in 1493, Christopher Columbus brought the seeds of oranges, lemons and citrons to Haiti and the Caribbean. They were introduced in Florida  in 1513 by Spanish explorer Juan Ponce de Leon, and were introduced to Hawaii in 1792.

Navel orange

A single mutation in 1820 in an orchard of sweet oranges planted at a monastery in Brazil yielded the navel orange,  also known as the Washington, Riverside, or Bahie navel. The mutation  causes navel oranges to develop a second orange at the base of the  original fruit, opposite the stem. The second orange develops as a conjoined twin in a set of smaller segments embedded within the peel of the larger orange. From the outside, it looks similar to the human navel.

Because the mutation left the fruit seedless and, therefore,  sterile, the only means available to cultivate more of this new variety  is to graft cuttings onto other varieties of citrus tree. Two such  cuttings of the original tree were transplanted to Riverside, California in 1870, which eventually led to worldwide popularity.

Today, navel oranges continue to be produced via cutting and grafting. This does not allow for the usual selective breeding methodologies, and so not only do the navel oranges of today have  exactly the same genetic makeup as the original tree, and are therefore clones;  in a sense, all navel oranges can be considered to be the fruit of that  single over-a-century-old tree. This is similar to the common yellow  seedless banana, the Cavendish.

On rare occasions, however, further mutations can lead to new varieties.

Valencia orange

The Valencia or Murcia orange is one of the sweet oranges used for juice extraction. It is a  late-season fruit, and therefore a popular variety when the navel  oranges are out of season. For this reason, the orange was chosen to be  the official mascot of the 1982 FIFA World Cup, which was held in Spain. The mascot was called "Naranjito" , and wore the colours of the Spanish soccer team uniform.

Blood orange

The blood orange has streaks of red in the fruit, and the juice is often a dark burgundy  colour. The fruit has found a niche as an interesting ingredient  variation on traditional Seville marmalade, with its striking red  streaks and distinct flavour. The scarlet navel is a variety with the same dual-fruit mutation as the navel orange.