Avena sterilis L.
Strong, rather stiff, erect green tufts to 150 cm, with heavy panicles. Leaf-sheath glabrous, or rarely with scattered soft hairs. Ligule 3-8 mm, truncate, or more tapered centrally, shortly denticulate, finely ciliate. Leaf-blade 15-45 cm × 3-15 mm, very finely scabrid on ribs, adaxially sometimes smooth, rarely with scattered hairs; margins minutely scabrid. Culm internodes glabrous. Panicle 20-40 cm, equilateral, lax; rachis smooth, branches few, widely spreading, filiform, scabrid. Spikelets often drooping; disarticulation above glumes; rachilla tough and continuous between florets. Glumes 9-11-nerved. Lemma elliptic-lanceolate, tough and hairy below level of awn insertion, greenish above and scabrid on nerves, narrowed to scarious bidentate apex; lower 1-2 lemmas awned; awn geniculate, column red-brown, twisted. Palea keels with 1-3 rows of cilia, interkeel usually minutely hairy above. Callus bordered by dense short hairs.