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AVENA L. Oat
Plant hermaphroditic, caespitose, annual. Culms erect or decumbent, glabrous; internodes hollow, terete. Leaves basal
and cauline, not distinctly distichous; sheaths terete, margins open; auricles absent; ligules membranous; blades flat
or involute, linear, lax. Panicles open, primary branches ascending. Spikelets solitary, laterally compressed
, disarticulation above glumes, awned or awnless, pedicellate (usually pedulous); florets 2-6, reduced
floret at apex or absent, callus hairy (pointed), rachilla not extended beyond upper floret; glumes 2 (large),
3-11-veined, equal, longer than first floret, glabrous, awnless or mucronate; lemmas 5-9-veined, coriaceous or
indurate, glabrous or hairy, apex bifid, awned or awnless; awns dorsal, awns straight or geniculate;
veins scabrous; paleas 2-veined, awnless, glabrous. Stamens 3; anthers yellowish or tan. Caryopses brown with pericarp
free, dorsiventrally compressed, elliptic. Base chromosome number x=7.
A small genus of about 27 species found in temperate areas. Our taxa are introduced from Europe and the
Mediterranean area. One species (A. fatua var. sativa) is an important cereal crop. The other taxa are disturbance
species.
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