Avena L., Sp. Pl. 1: 79. 1753; Gen. Pl. 5: 26. 1754; Bor, Grasses Burma, Ceyl. Ind. Pak. 432. 1960; Tutin et al., Fl. Eur. 5: 206. 1980; Sharma & Khosla, Grasses Punj. and Chandigarh 34. 1989; Wu & Phillips, Fl. China @ eFloras.org 22: 323; Fl. Pak. @ eFloras.org p. 504.

Annuals. Culms erect, fairly robust. Leaf blades linear, flat; ligule membranous. Inflorescence an open or rarely contracted panicle with large pendulous spikelets. Spikelets oblong to gaping (wide opened), 2-6-flowered, the lower 1-3 hermaphrodite, the others +/- reduced; rachilla pilose or glabrous, disarticulating below each floret or only below the lowest or not disarticulating (in cultivated species), rachilla not extended beyond the terminal floret. Glumes equal or subequal and as long as spikelet, lanceolate to elliptic, herbaceous to membranous, 7-11-nerved, back rounded, apex acuminate, persistent, awnless. Floret callus bearded. Lemmas lanceolate-oblong or ovate, shorter than or equalling the glumes, usually coriaceous, occasionally membranous, back rounded, 5-11-nerved, only 2 nerves reaching apex, dorsally awned usually from near middle, awn geniculate or straight, twisted at base, awn sometimes reduced or absent (cultivated species), apex bifid. Palea usually shorter and narrower than lemma, 2-keeled, keels ciliate. Stamens 3. Ovary densely hairy throughout or only at the top; stigmas 2. Caryopsis deeply furrowed.

27 species

Avena fatua L. Sp. Pl. 1: 80. 1753; Bor, Grasses Burma Ceyl. Ind. Pak. 434. 1960; Sharma & Khosla, Grasses Punj. and Chandigarh 35. 1989; Boiss, Fl. Or. 5: 543. 1884; Duthie, Fodder Grasses 51. 1888; Hook. f., Fl. Brit. India 7: 275. 1897; Wu & Phillips, Fl. China @ eFloras.org 22: 324; Fl. Pak. @ eFloras.org p. 508; Avena sativa var. sericea Hook. f., Fl. Brit. Ind. 7: 275. 1897.

Annual. Culms erect or geniculate at base, 30-110 cm tall, fistular, unbranched, 2-4 nodes, nodes hairy. Leaf sheaths terete, glabrous or basal sheaths puberulous; leaf blade flat, 20-35 cm x 1-1.5 cm, scabrid on adaxial surface and margins pilose; ligule ca. 5 mm long, white, membranous. Panicle narrowly to broadly pyramidal, open or more or less contracted, 10-40 cm long and up to 20 cm wide, nodding; branches horizontally spreading, scabrid. Spikelets pendulous, 1.7-2.5 cm long, florets 2 or 3, all florets awned; rachilla hairy, easily disarticulating below each floret at maturity; each floret with a bearded callus, callus hairs up to 4 mm long. Glumes subequal, as long as spikelet, persistent, lanceolate, herbaceous, back rounded, smooth, 9-11- veined, apex finely acute. Lemmas 1.5-2- 5 cm long, lanceolate-oblong, back rounded, 5-9-veined, densely hispid in lower half, green and scaberulous above, awned from near middle, apex papery, shortly 2-4-toothed; awn 2-4.5 cm long, geniculate, column thick, twisted, blackish brown, thin, tapering, scabrid, cream-colored above; palea shorter than lemma, 1.2-2.2 cm, 2-keeled, keels ciliate. Stamens 3. Ovary densely hairy. Caryopsis narrow oblong, ca. 3 cm x 3 mm, hairy, with long linear hilum.

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