Citrus Fruits, a group of edible fruits of the rue family. These fruits are an excellent source of vitamin C. They have thick, leathery skins and juicy, segmented pulps. Citrus fruit trees and shrubs are evergreen, usually thorny, and bear fragrant, white or pinkish-purple blossoms. Citrus fruits originated in eastern and southern Asia. They are grown commercially in most subtropical areas of the world. One of the leading producers is the United States, where most citrus fruits are grown in California and Florida.