The Key lime (Citrus × aurantiifolia)[1] 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 and seedier, with a higher acidity, a stronger aroma, and a thinner rind, than that of the Persian lime (Citrus × 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.