A four leaf clover refers to an aberration of a three leaf clover plant, the Trifolium repens or "white clover." The white clover is a deep green flowering vine with white blossoms. It is the original shamrock plant of Ireland and the unofficial state symbol. The shamrock already has powerful associations, and its occasional production of an extra leaf makes the rare four leaf clover especially lucky.

The three leaves of the white clover have become associated with the Christian Trinity, or God the Father, His Son, and The Holy Spirit. The extra leaf of the four leaf clover is said by some to stand for God's grace. A less dogmatic interpretation is that one leaf stands for faith, another for hope, the third for love and the last for luck.

One breeder of white clover, Yoke and Zoom, claim only about 1 in 10,000 plants will naturally mutate to produce a four leaf clover. They believe environmental stresses cause the mutation, and that a plant which mutates regularly is even rarer. However, through cloning, hydroponics and other methods, Yoke and Zoom claim to have increased the production of a four leaf clover on the Trifolium repens to 1 in 41 plants. Whether a purposely engineered four leaf clover would be considered as 'miraculous' is another matter. Yoke and Zoom reportedly pass on the clovers, sometimes leaving them for people to find in various places around London.

Many myths are associated with four leaf clovers. Finding one not only brings good luck, but in the Middle Ages, it was also thought to allow the bearer to see fairies and plant sprites. So it was that children often searched fields for a four leaf clover in order to see into the magical realm of the spirit world.

If hunting for a four leaf clover, don't be fooled by imposters. There are many clover plants that only bear four leaves. Pepperwort, also called Water Clover, and Oxalis are examples. Oxalis bears clover leaves that are narrow at the base with a reddish starburst center, while Pepperwort leaves resemble white clover in shape but are slightly rounder and a lighter shade of green. A genuinely rare, four leaf clover from Trifolium repens will usually have a smaller fourth leaf in comparison to the others on the stalk.

If you find a four leaf clover you can consider yourself very lucky indeed. When Adam and Eve left the Garden of Eden, legend has it that Eve was holding a four leaf clover. Curiously, the lore of the white clover plant is also associated with repelling snakes, though it didn't seem to work in the Garden of Eden!