White clover was introduced to North America by the Europeans because it is great as pasture crop. Most white clover has three leaves per stem, but sometimes it is possible to find one with four. It's not as hard as it sounds either, but it does take some patience. If you come across a patch of white clover, lie down in the grass and start looking. You should be able to find a four-leaf specimen in five or ten minutes. Some people believe that a four-leaf clover brings good luck. Whether it does or not, they are certainly interesting, and make a great conversation starter.