Lentils are symbolic of money. Their small, appearance resembles coins that swell when cooked so they are consumed with financial rewards in mind for the New Year.
In the Southern United States, it's traditional to eat or cowpeas in a dish called hoppin' john. The talk around the campfire was this legend that during the Civil War, the town of Vicksburg, Mississippi, ran out of food while under union attack. The town folk fortunately discovered black-eyed peas or cowpeas in the surrounding fields and the legume was thereafter considered lucky.