77. Avena Linnaeus, Sp. Pl. 1: 79. 1753.
燕麦属 yan mai shu
Authors: Zhen-lan Wu & Sylvia M. Phillips
Annuals. Culms erect, fairly robust. Leaf blades linear, flat; ligule membranous. Inflorescence a large loose panicle. Spikelets large, pendulous, oblong to gaping, florets 2 to several, the uppermost reduced; rachilla pilose or glabrous, disarticulating below each floret or only below the lowest, or not disarticulating (cultivated species); glumes lanceolate to elliptic, usually subequal and as long as spikelet, rarely strongly unequal or shorter than spikelet, herbaceous to membranous, 7–11-veined, back rounded, smooth, apex acuminate; floret callus acute to pungent, bearded; lemmas lanceolate-oblong, usually leathery, occasionally papery, back rounded, 5–9-veined, glabrous to hispid, awned usually from near middle of back, apex papery, 2-toothed to 2-fid, lobes sometimes extended into fine bristles, awn geniculate with twisted column, sometimes reduced or absent (cultivated species); palea usually shorter than lemma, keels ciliate. Ovary densely hairy. Caryopsis with long linear hilum.
About 25 species: centered on the Mediterranean region and SW Asia, extending to N Europe and N Asia, widely introduced to other temperate and cold regions; five species (all introduced) in China.
Avena includes several species cultivated as cereal crops (oats) and is also used for fodder and fiber production. A few species have become widespread as weeds of crops in temperate regions.
Avena barbata Pott ex Link and A. eriantha Durieu, native from the Mediterranean to C Asia, are mentioned (FRPS 9(3): 168. 1987) as cultivated in China.