Wheat is one of the world's most grown cereals.
There are several different species and subspecies.
Wheat is either free threshing (hulless), where the grains are easily loosened from the glumes, and non free threshing (hulled), where the grains are still enclosed by the glumes, and must be rubbed free in special mills.
There are varieties that are sown in spring (called spring types), and varieties that are sown in autumn (called winter types), and after the winter they are harvested the next summer. Winter types generally give a larger harvest than spring types.