Barley, common name for members of genus Hordeum of the grass family (Gramineae). Many wild and cultivated forms occur and, since all cultivated forms and some of the wild ones are interfertile, they are assumed to belong to one species, H. vulgare. Because of its ability to adapt to a wide range of soil and climate conditions, barley is widely grown in many parts of the world and was one of the earliest cultivated crops.
