How rare are four-leaf clovers?

Estimates tend to indicate that about one in every 10,000 clovers have four leaves. As far as true clover is concerned, the three-leaf variety is much more common than the four-leaf kind, which is why finding a clover with four leaves is considered by some to be lucky.

Some plants in the oxalis family look very similar to clover, and some of these naturally grow with four leaves. These plants are marketed as "lucky" alternatives to the standard three-leaf clover, but those who truly believe in the auspicious power of a four-leaf clover shouldn't be taken in. These plants aren't truly clovers, but simply look very similar.