Oranges are an extremely popular fruit crop, which are grown commercially in warm regions of the world. Oranges are eaten straight, used in a variety of deserts, made into marmalade, juiced and even used for their peels in seasoning. A diverse range of different strains of oranges are bred for sweetness, tartness, hardiness, flavor and other traits.
The round orange is the most common type of sweet orange. It is named after its round shape and uniform skin. Round oranges are generally sweet, but vary quite a bit by type. Some types of round oranges such as Hamlin oranges are nearly seedless, while others like pineapple oranges have many seeds. Round oranges also vary in flavor, size and season.
Marrs oranges, for example, have low acidity, moderately large fruit and are harvested in September. Valencia oranges, by contrast, are medium-sized with a balanced flavor and mature near the beginning of February.
Navel oranges are very similar to round oranges, but with one important difference. On one side of the navel orange a second, smaller fruit grows next to the main one. This fruit creates a little pouch in the orange and a small indentation that looks like a human navel. Navel oranges are easier to peel than most round oranges. They are not especially juicy, but are widely regarded for their flavor, which makes them excellent oranges for eating outright. They differ from most other sweet oranges in that they are sterile. They cannot be grown from seed, and must be grafted onto other orange trees.
The sour orange or bitter orange is a close relative of the sweet orange, and very similar in appearance. Bitter oranges have extremely bitter fruit and aromatic flowers and peels. Bitter oranges are used to make marmalade and are one of the ingredients in the liqueurs Grand Marnier, Triple sec and Curaçao. Bitter orange oil is also used in bergamot tea, certain colognes and perfumes, diet pills and as as an animal repellent.