Clovers

4 leaf clovers are pretty hard to find but once you find one, 

You will Usually find more around that one! 

The reason is because the 4th leaf is a mutation from the original 3

The clover plant is like, “Oh! That 4th leaf works really well! 

Lets Mutate to have that so we get more energy”

And so next spring it tries the 4 leaves, and it works

So really, 4 leaf clovers aren't that rare!