Is there a four leaf shamrock?
Actually a ‘shamrock’ is just another name for the yellow flowered clover, most clovers have three leaves but mutuations and fused leaves are fairly common, white clovers with 4, 5, 6, and more leaves are not even slightly rare and a couple of minutes search in a patch of clover would probably uncover several of them. At one time the British BBC Blue Peter program ran a competition for viewers to send in the clovers with the most leaves and I think that the winner had around 17.