Plants annual. Culms 40-180 cm, prostrate to erect when young,
becoming erect at maturity. Sheaths smooth or scabridulous; ligules 3-8
mm, acute; blades 8-45 cm long, 3-14 (25) mm wide, scabridulous. Panicles (6)20-40
cm long, 5-15 cm wide, nodding. Spikelets(18)25-32 mm (to 50 mm
in naked oats), with 1-2 florets (to 7 in naked oats); disarticulation not
occurring, the florets remaining attached even when mature. Glumes subequal,
(18)20-32 mm, 9-11-veined; calluses glabrous; lemmas 14-18
mm, usually indurate (membranous in naked oats), usually glabrous, sometimes
sparsely strigose, apices erose to dentate, longest teeth 0.2-0.5 mm, awns
usually absent, 15-30 mm when present, arising in the middle 1/3, weakly
twisted, not or only weakly geniculate; lodicules with a lobe or
tooth on the wings, this sometimes very small; anthers (1.7)3-4.3
mm. 2n = 42.
Avena sativa, a native of Eurasia, is widely cultivated in cool,
temperate regions of the world, including North America. Fall-sown oats
are planted in the Pacific and southern states in United States; spring-sown
oats are more important elsewhere in North America. It is sometimes planted
as a fast-growing soil stabilizer along roadsides. Several forms are grown,
of which the most distinctive are naked oats. These differ from typical
forms as indicated in the description and in having caryopses that fall
from the florets. Escapes from cultivation are common but rarely persist.
Avena sativa hybridizes readily with A. fatua. The hybrids are easily confused with fatuoid forms of A. sativa, which differ in having the sativa-type lodicule.
Much like no. 1 [Avena fatua L.], and hybridizing with it; herbage glabrous to scabrous; spikelets 2(3)-fld, the rachilla glabrous or only sparsely hirsute, not readily disarticulating; lemmas glabrous to sometimes scabrous, 3-7-veined, the callus naked or only sparsely bearded; awns, when present, (15-)22-35 mm, then only on the first lemma, not geniculate; 2n=42. European cultigen derived from no. 1, cult. throughout our range and often adventive in disturbed sites, but probably not persistent.
Gleason, Henry A. & Cronquist, Arthur J. 1991. Manual of vascular plants of northeastern United States and adjacent Canada. lxxv + 910 pp.