Citrus trees produce fruits called hesperidia. They are modified berries with a tough-leathery rind that contains volatile oil glands. The interior of the fruits is fleshy and split into segments. Citrus juice is rich in Vitamin C and citric acid that provide the characteristic taste of citrus fruits. Citrus crops were originated in tropical and subtropical Asia. The genus citrus contains a few species that provide all the current hybrid commercial lemons, limes, oranges, grapefruits, pomelos and clementines. They are grown in temperate, subtropical and tropical regions around the world.