# Hordeum

Hordeum is a genus of annual and perennial plants in the grass family. The species are native throughout the temperate regions of Africa, Eurasia, and the Americas.

## Taxonomy
### Species

Species include:
* Hordeum aegiceras – Mongolia, China including Tibet
* Hordeum arizonicum US (CA AZ NV NM), Mexico (Baja California, Sonora, Durango)
* Hordeum bogdanii – from Turkey and European Russia to Mongolia
* Hordeum brachyantherum – Russia (Kuril, Kamchatka), Alaska, Canada including Yukon, US (mostly in the West but also scattered locales in the East), Baja California
* Hordeum brachyatherum – Chile
* Hordeum brevisubulatum – European Russia; temperate and subarctic Asia from Turkey and the Urals to China and Magadan
* Hordeum bulbosum – Mediterranean, Central Asia
* Hordeum californicum – US (CA; OR; NV)
* Hordeum capense – South Africa, Lesotho
* Hordeum chilense – Argentina, Chile (including Juan Fernández Is)
* Hordeum comosum – Argentina, Chile
* Hordeum cordobense – northern Argentina
* Hordeum depressum – US (CA; OR; WA; ID; NV), British Columbia, Baja California
* Hordeum distichon – Iraq
* Hordeum erectifolium – northern Argentina
* Hordeum euclaston – Brazil, Uruguay, Argentina
* Hordeum flexuosum – Uruguay, Argentina
* Hordeum fuegianum – Tierra del Fuego
* Hordeum guatemalense – Guatemala
* Hordeum halophilum – Argentina, Chile, Bolivia, Peru
* Hordeum intercedens (bobtail barley) – California, Baja California
* Hordeum jubatum (foxtail barley) – widespread in US and Canada; Asiatic Russia, Inner Mongolia, Central Asia, Caucasus
* Hordeum × lagunculciforme – Iraq, Turkmenistan, Himalayas, western China
* Hordeum lechleri – Argentina, Chile
* Hordeum marinum (sea barley) – Europe, North Africa, southwestern and central Asia
* Hordeum murinum (wall barley) – Canary Islands, Europe, North Africa, southwestern and central Asia
* Hordeum muticum – Argentina, Chile, Bolivia, Peru
* Hordeum parodii – Argentina
* Hordeum patagonicum – Argentina, Chile
* Hordeum × pavisii – France
* Hordeum procerum – Argentina
* Hordeum pubiflorum – Argentina, Chile
* Hordeum pusillum (little barley) – widespread in Canada and US; northern Mexico, Bermuda, Argentina
* Hordeum roshevitzii – China, Korea, Primorye, Mongolia, Siberia, Kazakhstan
* Hordeum secalinum – Europe, Mediterranean, Caucasus
* Hordeum spontaneum – from Greece and Egypt to central China
* Hordeum stenostachys – Brazil, Argentina, Uruguay, South Africa
* Hordeum tetraploidum – Argentina, Chile
* Hordeum vulgare (barley) – native to the Middle East, now cultivated in many countries

#### Formerly included species

Botanists now regard many species as better suited to other genera: Arrhenatherum, Crithopsis, Dasypyrum, Elymus, Eremopyrum, Hordelymus, Leymus, Psathyrostachys, and Taeniatherum.

### Etymology

The name Hordeum comes from the Latin word for "to bristle" (horreō, horrēre), and is akin to the word "horror".

## Distribution

The species are native throughout the temperate regions of Africa, Eurasia, and the Americas.

## Ecology

Hordeum species are used as food plants by the larvae of some Lepidoptera species, including the flame, rustic shoulder-knot and setaceous Hebrew character.
Some species have become weeds introduced worldwide by human activities, others have become endangered due to habitat loss.

## Uses

One species, H. vulgare (barley), has become of major commercial importance as a cereal grain, used as fodder crop and for malting in the production of beer and whiskey.