Oranges are the fruit of several small trees and shrubs in the genus Citrus, cultivated for human consumption.
Oranges are native to tropical Asia, where they have been cultivated since prehistoric times. Today they are grown in tropical and subtropical zones all around the world. They grow best with light frosts in winter, but a heavy frost will ruin the fruit crop.
The sweet orange is the standard, grocery-store variety. It is eaten raw, by itself or in fruit salads, or as a flavoring for various sauces and baked goods. In the United States of America, frozen concentrated juice is the biggest ultimate use of the crop.
The Seville orange, also called the bitter or sour orange, has too high a concentration of acids to be eaten directly; instead, it is used to make marmalade.
Other edible varieties are the Jaffa orange, native to Israel; the blood orange or Maltese orange, which has red pulp; and the navel orange.