Description:

• Annual
• Leaf blade linear, expanded, flaccid; ligule an unfringed membrane
• Inflorescence an open panicle; spikelets pedicelled, pendulous
• Spikelet large, 7-46 mm long, laterally compressed, disarticulating above glumes, sometimes between florets (persistent in cultivated forms); glumes persistent, ± equal, usually as long as to longer than spikelet, similar, membranous, margin hyaline, rounded on back, 3-11-nerved, apex acute to acuminate, awnless
• Florets 2-several; lower (1)2-6 florets bisexual; upper florets ± reduced; lemma similar in texture to glumes, membranous when immature, later becoming indurated, hairy to glabrous, 5-9-nerved, not keeled, 2-lobed, lobes awned or awnless, awn dorsal, or absent in some species and cultivars, inserted at middle or higher, geniculate, longer than body of lemma, twisted below, rarely straight; callus short, obtuse to acute, usually hairy; palea shorter than lemma, 2-keeled, 2-nerved, membranous
• Lodicules 2, relatively large
• Stamens 3
• Ovary densely pilose; styles short, plumose
• Caryopsis oblong to ellipsoid, hairy or glabrous
• x = 7 (high polyploidy)

Nomenclature:

• *Avena L.
  • Linnaeus: 83 (1753)
  • Stapf: 477 (1899)
  • Chippindall: 80 (1955)
  • Baum: 12 (1968)
  • Launert: 74 (1971)
  • Baum: 1 (1977)
  • Rocha Afonso: 206 (1980)
  • Hubbard: 81 (1970)
  • Clayton & Renvoize: 124 (1986)
  • Gibbs Russell et al.: 58(1990)
  • Watson & Dallwitz: 158 (1994)

Distribution & Notes:

• Global: Species ± 25, mainly Mediterranean and Middle East
• Southern Africa: Species 5, naturalised, not in Namibia and Botswana, mainly escapes from cultivation