Endosperm
The endosperm of cereal plants can be a source of energy for humans. Wheat endosperm is ground into flour for bread. With whole wheat bread the bran (cover of seed) and the germ 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.