Hordeum is a genus of annual and perennial plants in the grass family. They are native throughout the temperate regions of Africa, Eurasia, and the Americas. One species, H. vulgare (barley), is of major commercial importance as a cereal grain, used as fodder crop and for malting in beer and whiskey production. Some species are nuisance weeds introduced worldwide by human activities others endangered due to habitat loss. Hordeum species are used as food plants by the larvae of some Lepidoptera species, including the flame, rustic shoulder-knot and setaceous Hebrew character.