Plants annual or perennial. Culms 8-200 cm, erect or decumbent. Sheaths open; auricles absent; ligules membranous; blades usually flat, sometimes involute, lax. Inflorescences panicles, diffuse, sometimes 1-sided. Spikelets 15-50 mm, laterally compressed, with 1-6(8) florets; rachillas not prolonged beyond the uppermost floret; disarticulation above the glumes, usually also between the florets, or cultivated forms not disarticulating. Glumes usually exceeding the florets, membranous, glabrous, 3-11-veined, acute; calluses rounded to pointed, with or without hairs; lemmas usually indurate and enclosing the caryopses at maturity, 5-9-veined, often with twisted, strigose hairs below midlength, apices dentate to bifid or biaristate, awns (if present) dorsal, usually once-geniculate and strongly twisted in the basal portion; paleas bifid or entire, ciliate on the keels; lodicules 2, free, glabrous, toothed or not toothed; anthers 3; ovaries hairy. Caryopses terete, ventrally grooved, pubescent; hila linear. x = 7. Name from the Latin avena, oats.
Avena, a genus of 29 species, is native to temperate and cold regions of Europe, North Africa, and central Asia; it has become nearly cosmopolitan through the cultivation of cereal oats and the inadvertent introduction of the weedy species. Six species have been introduced into the Flora region.
Reports of Avena strigosa Schreb. from California are based on misidentifications. The specimens involved belong to Avena barbata.
SELECTED REFERENCEBaum, B.R. 1977. Oats: Wild and Cultivated. A Monograph of the Genus Avena L. (Poaceae). Biosystematics Research Institute Monograph No. 14. Supply and Services Canada, Ottawa, Ontario, Canada. 463 pp.