Avena fatua L.

Family: Poaceae, Tribe: Aveneae

Pertinent Synonyms & Notes (particularly those used in California; go to GRIN for other synonyms)


Pertinent Common Names (particularly those used in California; go to GRIN for other common names)

wild oat

Primary Disseminule Type


Description (diagnostics are in brown)

Spikelets solitary, consisting of 2–3 fertile florets and a barren rachilla extension, cuneate, laterally compressed, 18–32 mm long, breaking up at maturity, disarticulating below each fertile floret.

Glumes persistent, similar, lanceolate, 18–32 mm long (exceeding tips of florets), membranous and thinner than fertile lemma, without keels or awns, 7–11-veined, gaping, apices acuminate. Upper glume 1.2–1.4 length of adjacent fertile lemma.

Florets: rachilla persistent, pilose, tip diamond-shaped, callus obtuse, hairs up to 5.5 mm long and dense, disarticulation scar oblique, round, ovate or triangular.

Lemma lanceolate, 14–22 mm long, coriaceous, straw-colored to dark brown, without keel, 5–9-veined, surface densely strigose on the lower third and glabrous above, apex dentate, 2–4-fid, teeth 0.3–1.5 mm long and glabrous, awn dorsal, arising about half-way up or more on the back of lemma, bent once, twisted and dark brown below bend, 20–42 mm long overall.

Palea about the size of lemma, keels ciliate.

Caryopsis 6–8 mm long x 1.8–2.2 mm wide, compressed dorsiventrally, ventrally longitudinally grooved, light brown, densely hairy, hilum linear.

Similar Species

Similar Species Comparison Chart

Risk Assessment (codes in yellow or red indicate cause for concern; assessments are current as of mid-2011; click AUQP, NZBORIC, or NZBPI for access to the most recent versions of these databases and possible assessment changes)