Like many myths from Ireland, the shamrock, may be a sham according to scientists. The plant with mystical attributes will have to compete in the rich fields of clover to find its true botanical roots.

Legend holds that Ireland’s patron saint, St. Patrick, plucked a three-leaf clover from the ground as a symbol of the Holy trinity. The much rarer four-leaf clovers later took hold in Irish folklore as tokens of luck. But even as shamrocks sales soar in garden stores this week, the legendary plant continues to perplex botanists. At least six species of plant can claim to be the shamrock, says botanist Michael Vincent of Miami University. Some, like wood sorrel, aren’t clover at all, although they do better houseplants than the sun-greedy clovers they mimic.

The shamrock’s elusive identity isn’t surprising, since the clover group alone may include as many as 300 species, many still undiscovered. And while 99% of clovers have three leaves, finding a clover with four, five, six or more leaves requires more patience than luck, Vincent says. He once found a clover with 21 leaves.

The shamrock and its kin may actually turn out to be much more practical than magical. Cattle eat it, bees use its nectar, and soil grows richer in its presence. Red clover tea may fight cancer and respiratory illnesses. Breeding projects currently underway could improve the plant and its ecological value-even this side of the rainbow.

As far as luck goes, the search for that gene has yet to begin. Few outside the Emerald Isle, in fact, even have enough faith to look.