Of course, the rarity of four-leaf clovers makes some people who find them feel as if luck is on their side. Among naturally occurring clovers, the odds of finding a four-leaf clover instead of the more common three-leaf clover is 10,000 to 1. It may take some effort and quite a bit of luck to locate one with four leaves, and a five-leaf clover is considered by many to be unlucky.
Since the 18th century, the shamrock has been a symbol of Ireland. It was used as an emblem by rival militias and later was incorporated into the Royal Coat of Arms in the United Kingdom, alongside the rose of England and thistle of Scotland.
— Daily News