Tufted annuals. Leaves flat. Inflorescence a dense linear spike; rachis disarticulating or not at maturity. Spikelets 1(–2)-flowered, in threes along the rachis and falling united in species with disarticulating rachis, the lateral pair male and pedicellate or bisexual and sessile, or reduced to rudiments; glumes narrowly linear-lanceolate, usually awned, those of the outer florets usually differing from the inner and both abaxial to lemma; lemma of fertile floret(s) 5-nerved, unkeeled, awned; stamens 3.
About 40 species from temperate Africa, Eurasia and North and South America.
Barley (H. vulgare L.) and Two-row Barley (H. distichon L.) are widely cultivated for the grain which is used in brewing as well as food for humans and stock. The cultivated barleys differ from other species of Hordeum in have non-shattering rachises which has led to the latter being placed in the genus Critesion Raf., but molecular studies show the difference between the two genera to be unsupported.