The iconic clover-like symbol known as the "Shamrock" that has been the face of Irish pride and St. Patrick's day in particular for as long as we can remember. However, the brutal reality is no one actually knows what a shamrock is, and its origins are about as clear as the green beer you'll be sloshing down.

A Sham-what?

It should first be pointed out that no one plant is a shamrock. None boast that common name, nor does any plant species or even genus resemble the word. That's at least according to the Smithsonian Institute's Bess Lovejoy, who recently took a detailed look at the "sham" of the shamrock's name.

Lovejoy explained that "shamrocks" first appeared in plays and poetry in the 1500s, and by the end of that century, an English herbalist named John Gereard noted that the common meadow trefoil, known as the clover, was likely what the Irish called Shamrockes [sic].

There's just one problem with that quick-and-easy classification: there are four common clover species native to Ireland, and none of them resemble the three-leafed symbol to a T.

Looking to a do a bit of lucky lawn work, About.com's resident landscaping expert David Beaulieu managed to dig up a survey conducted at the National Botanic Gardens, in Glasnevin, Dublin, which asked locals which of the four clovers was the proper one to wear pinned to your chest on St. Patrick's Day.

Unsurprisingly, it turned out that the Irish can't even agree which is the true "shamrock," with 46 percent of those surveyed found wearing the lesser trefoil (Trifolium dubium) and 35 percent wearing the white clover (Trifolium repens). The remaining merry-makers were found to be wearing Red clovers (Trifolium pratense) (~4%), Black medicks (Medicago lupulina) (~7%), and even a few various members of the Oxalis genus.

It's important to point out that as these plants mature, they begin to look startlingly different, flowering in dramatic ways or letting their once-recognizable leaves take on a dark bronze hue. (Scroll to read on...)

Still, St, Patrick's day is at the start of spring, when most of these plants will be young - resembling tiny shamrocks for vendors to sell or passersby to pick and pin. It's then no wonder why there's a bit of confusion.

The Particulars on Patrick

This then makes it simple enough to grab any three-leafed lobed plant and call it a "shamrock." This is probably exactly what St. Patrick himself did when bringing an understanding of Christianity's Holy Trinity to the people of the Emerald Isles.

As common legend has it, the missionary and saint used the shamrock to help spread Roman Catholicism, and practitioners would wear such a plant on their chest or hat to help recognize a shared faith - as opposed to wearing a more obvious symbol, such as a crucifix.

There is irony there then, as Caleb Threlkeld, a British minister and doctor wrote in his description of the white clover, as part of his Synopsis Stirpium Hibernicarum.

"It being the current tradition that by this 3-leafed emblematically set forth the mystery to [the Irish] of the Holy Trinity," he said. "However that be, when they wet their Seamar-oge [shamrock], they often commit Excess in Liquor ... generally leading to debauchery."

It's often misstated that St. Patrick brought Catholicism to the Isles, but historians know that he actually arrived long after the faith became popular there, and served under Ireland's first bishop. He is instead more likely a man who is celebrated for making the faith widespread, using the good ol' (albeit confusing) shamrock as a means to an end. Today, nearly three fourths of Ireland's entire population is Roman Catholic, which explains why St. Patrick's feast day - the day of his death - is such a popular holiday. (Scroll to read on...)

A Four-Leafed Farce!

And yet this does nothing to explain the obsession over four-leafed clovers, as four leaves has nothing to do with the St. Patrick legend. As with many Christian holidays, we can perhaps look to Pagan traditions for the answer.

Christian missionaries were certainly not dumb people. Dedicated to spreading a new faith in old worlds, they often took the traditions that locals already held dear and married them with Christian values. This may then best explain why the four-leafed clover is so closely associated with St. Patrick's feast day.

According to Celtic polytheism, a four leaved clover - due to its rarity in nature - was a sign of very good luck and could even ward off evil. It's been argued that not soon after this was learned, word was spread that Eve carried a four-leafed clover out of the Garden of Eden, explaining why the lucky aberration was on Earth.

There was no better advertisement missionaries could have asked for than to slap a clover on a few locals and tell them they had one more reason to celebrate... just as long as they gave thanks to St. Patrick and God.

However, when there's money to be made, you can bet your lucky greens that someone's going to jump right on it. As Catholicism spread and Ireland's favorite feast day became increasingly popular, vendors in North America and eventually Ireland began to sell Oxalis deppei - a bulbous plant from Mexico that not only looks like the iconic shamrock, but also always has four leaves. (Scroll to read on...)

Now sold around the world, it could be argued that trade and tradition have made this foreigner the true lucky leaf. Still, this ornamental plant isn't even a true clover, and as there is no chance involved, you'd be hard-pressed to make the argument that those leaves are lucky.

The take away from all this? Holidays are strange things, and if a Catholic saint's feast day has somehow evolved into a day of floats, green beer, and Mexican plants, I shudder to think what March 17th will look like in the centuries to come.

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- follow Brian on Twitter @BS_ButNoBS