A species of wheat distinct from wheat used to make bread and other bakery products. The hard, flinty kernels of durum wheat are specially ground and refined to obtain semolina, a granular product used in making pasta items such as macaroni and spaghetti. Most durum wheats are grown in Mediterranean countries, the former Soviet Union countries, North America, and Argentina. U.S. durum production is centered in North Dakota with other producing states being South Dakota, Minnesota, Montana, California, and Arizona.