Scientific Name

Avena fatua L.

Common Name(s)

Wild oat

Tribe / Family Name

Poeae

Flowering Period

June to September

Symbol

AVFA

Description

Wild oat is an introduced cool-season annual bunchgrass that reproduces from seeds. Culms range from 8–160 cm in height. The inflorescence is an open panicle that is 7–40 cm long, up to 20 cm wide, and somewhat nodding. Spikelets are 2- to (sometimes) 3-flowered; disarticulation beneath each floret. Glumes are subequal, 18–32 mm long, acute, glabrous, papery, 9- to 11-nerved, and usually exceeding the florets. Lemmas are 14–22 mm long, smooth throughout or hairy below midlength, bifid at the tips (teeth up to 1.5 mm long), 5- to 7-nerved, and awned (awns 28–45 mm long, twisted and geniculate, reddish brown to blackish, and arising at mid-length); callus densely bearded. Sheaths are open and glabrous to pubescent. Auricles are absent. Ligules are 4–6 mm long, membranous, acute to obtuse, erose-ciliolate, and glabrous or often pubescent. Blades are 10-45 cm long, up to 15 mm wide, flat, glabrous to pilose along the margins (especially near the base), and scabrous above and below.

General Info

Wild oat can be found on roadsides, agricultural land, valleys, foothill ranges, and other disturbed sites.

Similar Species

Wild oat looks similar to slender oat (Avena barbata). To differentiate between them, check the lengths of the bifid lemmas: those of wild oat are up to 1.5 mm long, and on slender oat, the bifid lemmas are up to 5 mm long. Another similar species is common oat (Avena sativa). Unlike wild oat, common oat generally lacks hairs on the lemmas, has 2 florets, and can either be awnless or have short, straight awns.