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UF/IFAS Extension University of Florida

Plant Identification Learning Module:
Fruits & Nuts

Key Lime (Citrus x aurantiifolia)

The key lime is a shrubby citrus tree, to 16 feet, with many thorns. The trunk rarely grows straight, with many branches that originate quite far down on the trunk. The leaves are ovate, one to three inches long, resembling orange leaves. The flowers, one inch in diameter, are yellowish white with a light purple tinge on the edges. Flowers and fruit appear throughout the year but are most abundant from May to September. The key lime is a round fruit that is yellow when ripe but usually picked green. It is smaller, seedier, has a stronger aroma, and a thinner rind than that of the Tahiti 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.

Limbs of a key lime tree with round green fruit and medium sized green oval, pointed leaves
Martin Reith, some rights reserved.
Key lime foliage, showing a thorn on the stem.
Scott Zona, some rights reserved.
Two small white, star-shaped flowers of a key lime tree.
Asael Bonfada, some rights reserved.
Key limes are actually yellow when ripe. They're very round. This photo shows one Key lime whole and yellow, and another cut open to show the light yellow-green translucent flesh.
Jonathan H. Crane, UF/IFAS.
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