Avena sativa L.
oat
Erect, green to glaucous tufts, 50-150 cm. Leaf-sheath glabrous or slightly hairy. Ligule (2)-3-5 mm, ± rounded, finely denticulate, abaxially finely scabrid. Leaf-blade 15-40 cm × (2.5)-7-15 mm, ± finely scabrid on ribs; margins finely scabrid, sometimes with a few scattered hairs. Culm erect or decumbent and rooting at base, internodes glabrous. Panicle 14-32 cm, very variable in shape, loose or contracted, equilateral to secund; branches horizontal to ± erect, slender, finely scabrid. Spikelets (15)-20-30-(40) mm, 2-(3)-flowered, pendulous on fine unequal pedicels; falling intact at maturity. Glumes 9-11-nerved. Lemma 10-18 mm, ovate-lanceolate, glabrous, or with a few hairs towards base, apex obtuse or shallowly notched, red-brown, grey, yellow, white or blackish, usually awnless, but lowest or sometimes all florets in certain cultivars bearing a weak, straight or curved awn, not geniculate and scarcely twisted at base. Palea keels with 1 row of cilia, interkeel scabrid or glabrous. Anthers 2-4.2 mm. Caryopsis 4-9 × 1.5-3 mm.
N.; S.; Foveaux Strait on Pig Id; St.; C. On roadsides, on railway em-bankments, and near racecourses and in farmland, occasionally in damp ground.
Naturalised from Eurasia.
Fatuoid oats, a mutant form of oat, were first recorded for N.Z. by Wright, G. M. and Shillito, N. L. N.Z. J. Agric. 128: 45 (1974). Fatuoids, or false wild oats, occur spontaneously in oat crops. Their florets resemble those in A. fatua; the awn is geniculate with twisted column, and the callus horse-shoe shaped and bordered by hairs. The spikelet disarticulates below all florets at maturity. In other respects fatuoids resemble the oat cultivar within which they appear. Fatuoids may seem taller than other plants in the crop because they shed their florets early and the empty glumes stand out above the drooping grain-filled spikelets of normal plants.
