The Key lime is a citrus species with a globose fruit, 2.5-5 cm in diameter (1-2 in) that is yellow when ripe but usually picked green commercially. It is smaller, seedier, has a higher acidity, a stronger aroma, and a thinner rind than that of the Persian lime (Citrus x latifolia). It is valued for its unique flavor compared to other limes, with the key lime usually having a more tart and bitter flavor. The name comes from its association with the Florida Keys, where it is best known as the flavoring ingredient in Key lime pie. It is also known as West Indian lime, Bartender’s lime, Omani lime, Tahitian lime or Mexican lime, the latter classified as a distinct race with a thicker skin and a darker green color.
C. AURANTIFOLIA is native to Southeast Asia. Its apparent path of introduction was through the Middle East to North Africa, thence to Sicily and Andalusia and via Spanish explorers to the West Indies, including the Florida Keys. The lime cultivation from the Caribbean spread to tropical and sub-tropical North America, including Mexico, Florida, and later California.
Since the North American Free Trade Agreement came into effect, many Key limes on the US market are grown in Mexico and Central America. They are also grown in Texas and California.