Popcorn or popping corn is a type of maize which puffs up when it is heated in oil or by dry heat. Special varieties of corn are grown to give improved popping yield. Some wild types will pop, but the cultivated strain is Zea mays L. subsp. mays (Everta Group), which is a special kind of flint corn. First developed by precolumbian Native Americans, popcorn is now a popular snack food all over the world.