Although the shamrock and Lucky Clover are both from the white clover plant, one has four leaves. The four-leaf clover is believed to most likely be a genetic mutation, of a variety of white clover, known as “Trifolium Repens.” Trifolium means three-leafed. Generally, all leaves of the stem are the same size.

The cause of what causes four leaves remains a mystery, but it is thought that a recessive trait in the white clover plant causes an unusual amount of leaves to sprout, usually four, because the recessive trait is inherited from both its parents. It is sometimes thought that warm weather encourages the sprouting of the four-leaf clover.