Four-Leaf Clover Cross
"Depend on the lucky rabbit's foot if you must, but remember, it didn't work for the rabbit." (Anon)
"Luck is what happens when preparation meets opportunity. And many an opportunity is lost because a man is out looking for four-leaf clovers." (Anon)
Four-Leaf Clover Cross
The Irish for 'Clover' is Seamaróg, which has been anglicised as Shamrock.
Finding a clover with four leaflets is rare, and since exceptionally good luck is also rare, it is logical (for some people) to associate the four-leaf clover with good luck.
Exceptionally bad luck is just as rare, of course, so why should the four-leafed clover favour good luck? Nobody seems to know, but it's possibly because the leaves are heart-shaped.
Recognise that these four leaflets symbolise the four arms of a cross, and your good luck will come from the Blessed Jesus. The three-leaf clover reminds us of Faith, Hope, and Love (see also Budded Cross). The extra leaflet on the four-leaf clover is for Luck.
If only all that were true!
You don't need to delve too deeply into basic biology to see that plant mutations happen all the time. The four-leaf clover is just a three-leaf clover that's had an accident, either genetically or environmentally.
There are also two-leaf clovers, single-leaf clovers, and very occasionally, clovers with more than four leaves. Indeed, with an appropriate laboratory, research and inclination, it is possible to engineer four-leaf clovers artificially. Whether they would be considered to have the same luck as those found in the wild, well, you'd need to consult another website about that.
If you have Faith, Hope, and Love, you don't need any Luck.
Other 'lucky' pages:
In 2010 researchers at the University of Georgia in Athens and The Samuel Roberts Noble Foundation in Ardmore, Oklahoma, managed to identify the gene that controls whether clover develops into the common variety with three leaves or four leaves.
This was not an attempt to mess with the supernatural; rather they are looking at ways to mess with the natural, and engineer plants that provide more nutritious fodder for beef cattle.
Cows will no doubt just chomp away at these four-leaf varieties. They are not known to be particularly superstitious.