There are three main groups of varieties: the "Navel" group, characterized by its navel and its consumption in fresh, the group of "Blancas", without navel, frequently used in the juice industry and the group of the "Sanguinas", distinguished of the rest by their characteristic reddish colour, both in their flesh and rind.

Within the group of citric oranges, we distinguish two species: sweet orange and bitter orange. The fruits of the latter do not have much commercial importance for consumption in fresh; that is why only the different varieties of sweet orange appear below.

1 Group "Navel"

The Navel orange is the best one as table fruit, since its use in industry is restricted, for example, it is not used in juice processing, since it produces less quantity. Moreover it develops a bitter flavour due to a compound existing in a very small quantity, called limonine, only given off when the orange is squeezed.

The name ‘Navel’ is due to the appearance of its small rudimentary fruit, which joins to the main fruit by its style area (opposite to the place where fruit and leaves join). The appearance is similar to a navel.

"Navel" oranges are precociously matured and bear big seedless fruits due to different degenerations (pollen, embryonic sac, etc.). Its rind is easily peeled, its colour is intense orange and it has a sweet and pleasant flavour.

In spite of having greater climatic restrictions, oranges represent great part of the citrus production of Spain, Morocco, Turkey, South Africa, California, Australia, Uruguay and Argentina.

The most important varieties of this group are:

- Navelina: Original from California, it did not arrive to Spain until 1933, when the University of California supplied it to the Valencian Institute of Agrarian Research, IVIA, where it was given the name "Navelina.
- Washington Navel: Its origin is uncertain although it is thought to come from a Brazilian mutation.
- Newhall: It is a mutation of the "Washington Navel", original from California. The characteristics of the tree and the fruit are practically those of the "Navelina’, except their maturation period, which takes place a bit earlier.
- Navelate: Original from Spain, it is a mutation of "Washington’.
- Lane late: Coming from Australia, its origin is a mutation of the variety Washington Navel.

2 Group "Blancas"

This name was formerly used to distinguish them from the Navel or the blood varieties.

Their main characteristics are the lack of navel in their fruits, an inferior acidity compared to other groups of varieties and the absence of the bitter flavour in their juice.

The most important varieties of this group are:

- Salustiana: It comes from a spontaneous mutation of the variety Comuna at the end of the 40’s in Enova, a province in Valencia, Spain. It is the second most cultivated variety in the group of "blancas" in Spain, occupying an approximated area of 4000 has, which represents 6% of the surface devoted to orange culture in Spain.

- Valencia Late: Its origin is somehow confusing. It was first known in the Azores Islands, at the end of the last century. From there it was taken by the English to Florida and later on to California, and finally imported to Spain. Other authors are sure about its Portuguese origin.

It has extraordinary qualities that make it, nowadays, the most important orange in the world, being the leader variety in many producing countries like Argentina, Australia, California, Florida, Morocco, Uruguay, etc.

3 Group "Sanguinas"

Formerly, it was thought that this group had its origin in the Mediterranean area but recently it has been found out that it is original from China.

The oranges of this group are very similar to the "Blancas" but they are different when cultivated in conditions that favour the red pigment synthesis in the flesh and juice, and even sometimes in the skin. For this to happen, there must be low night temperatures and wait until autumn or winter in the Northern Hemisphere so the fruit acquires its reddish tone.

These oranges are not suitable for industry since the pigments usually provide a dark colour to the juice. Nevertheless, in Italy they produce an attractive and refreshing blood orange juice similar to the tomato juice.

In Spain the production of this variety has diminished, not reaching 1% of the total production of oranges.

Some other appreciated varieties are: "Doblefina, "Entrefina, "Sanguinelli.

Some orange varieties

"Navelina ‘
Fruit with an intense reddish colour, average size and oval shape in the navel area. It is a precocious maturing orange, harvested from the end of October.

The tree never reaches great size although it is an adult tree. Its great leaves have a very dark green colour.

"Washington Navel"
The fruit has an average to large size, round or slightly oval, slightly rough bark, thick, easy to peel. The gores separate easily and contain a firm flesh, full of pleasant flavoured juice and a balanced acid content.

Great size and vigorous tree. It has little adaptability to extreme climatic conditions such as dry and hot weather conditions while flowering, that is usually abundant.

It is a variety of early to middle harvesting, although at the moment it has moved to mid winter because of the mandarins and the precocious variety Navelina.

"Navelate’
Medium to large fruit, although a bit smaller than Washington, of yellow-reddish colour. It is of thin skin and long or round shape. The flesh is also thin, with a high pleasant juice content and balanced acid content. All these qualities make this variety the best one in Spain.

Its maturations delayed with respect to " Washington Navel" and may stay in the tree during at least three months without losing its quality. Its harvesting usually begins at the end of December or beginning of January.

The tree is similar to the variety Washington Navel, although it has a great amount of strong and sharp thorns in its branches and shoots. It has a low productivity.

"Lane late‘
The fruit is similar to " Washington Navel", although with a thinner rind and a less marked navel. Its juice contains less bitter principles.

It is a vigorous tree of intense foliage and dark green leaves with thorns in their axils.

An important characteristic is the slow maturation of its fruits, since they can stay in the tree until May, although in warm climates they may loose juice, limiting its harvesting period.

"Salustiana ‘
This fruit ripens in December in the Northern Hemisphere but does not reach its best until the end of January. It can even stay in the tree until May without suffering quality losses. Medium to large size, little intense colour, slightly rough rind and seedless.

It is a vigorous tree, medium to large size, with a tendency to form vertical branches, distinguishing it from other varieties.

"Valencia Late ‘
Medium to large fruit, spherical or slightly elongated. It has an intense or somehow pale colour and its rind is slightly rough but thin.

It is practically seedless and the flesh has a high juice content with a sometimes attractive colour and slightly acid.

It is a vigorous tree, with a good development, tendency to verticality, very well-adapted to different climates and grounds.

It is the most delayed variety of all the sweet oranges. It is harvested in March, although it may stay in the tree several months without losing its quality. Nevertheless, when temperatures rise it tends to grow green again. The later it is collected, the smaller the next harvest is, due to the influence of the fruit in the next year’s flowering.

Group sanguinas

Medium to small fruit, long or round shape, thin rind and high juice content. They have the distinguishing red colour flesh, juice and skin, due to the so-called anthocianin pigments. Its flavour is similar to raspberries or cherries, being this characteristic much in those varieties of intense flesh coloration.

The trees are small, with a dense foliage, clear colour and irregular decolouring in the leaves.

Its low productivity, its small size and the development of navel varieties of better quality has caused the loss of its commercial importance.

Within this group stand out the varieties Doble fina, Maltaise Sanguine, Moro, Sanguinelli, Tarocco, Tomango, Washington Sanguina, etc.