Ordinary corn is hard grain type, also called flint type. The seeds are mostly square, the endosperm at the top and around is horny, and only the near embryo part in the center is silty, so the appearance is translucent, shiny, hard and full. The grain color is mostly yellow, and occasionally white, red, purple and other colors. Grain is of good quality and has a long history of cultivation in China. It is mainly used for eating. The corn fried with popcorn exploded. The seeds are small, rice-shaped or pearl-shaped, the endosperm is almost horny, the texture is hard and transparent, and the seed coat is mostly white or red. Many shops can buy corn for popcorn.