"The world record for the most leaves on a clover stem is 18 and was discovered by Shigeo Obara of Hanamaki City, Iwate, Japan on May 25, 2002. " Guinness World Records 2010. But June 3rd a 22 leaf clover was discovered, no one has found a 23 leaf clover
A four leaf clover is a common 3 leaf clover with a mutation which makes it grow a fourth leaf. According to Irish tradition, a 4 leaf clover brings good luck to their finders, especially if it's found accidentally.