The endosperm of cereal plants is an important source of nutrition for humans. Wheat endosperm is ground into flour for bread. With whole wheat bread the bran (cover of seed) is also in the flour. Barley endosperm is the main source for beer production. Other examples of edible endosperms are coconut 'meat' and coconut 'water', and corn, including popcorn. Some plants, like the orchids, lack endosperm in their seeds.