Sterile oat

Avena sterilis (sterile oat, animated oat) is a stout, broad-leaved annual grass of the family Poaceae, growing on robust hollow erect culms up to about 1.5 m tall. The flat, ribbed, mid-green leaf blades are large and broad for an oat, reaching up to 60 cm long and 6–14 mm wide, with slightly rough margins and a long blunt membranous ligule. The inflorescence is a loose, open, spreading to slightly one-sided panicle 15–40 cm long bearing large pendulous spikelets, each spikelet 25–40 mm long and typically containing three (sometimes two to five) florets enclosed in long thin papery glumes; the lower two florets generally bear a stout, sharply geniculate dorsal awn 3–9 cm long that twists hygroscopically and helps drill the seed into soil. The lemmas are softly hairy at the base in straw-yellow to slightly reddish tones. Native to the Mediterranean Basin and through western, central, and southern Asia, A. sterilis is now widely naturalised on every continent except Antarctica, growing as a competitive weed of cereal crops, fallow land, roadsides, and disturbed open ground.