Description from Flora of China
Avenella (Bluff & Fingeruth) Drejer; Aira sect. Avenella Bluff & Fingerhuth.
Perennials, densely tufted. Leaf blades mainly basal, linear to setaceous, flat, folded or rolled; ligule membranous. Inflorescence usually an open panicle, infrequently contracted or spikelike; branches and pedicels usually filiform. Spikelets oblong to gaping, shining, laterally compressed, florets 2–3(–5), disarticulating below each floret; rachilla pilose, extended beyond uppermost floret; glumes lanceolate to oblong, subequal, ± equaling spikelet, membranous, shining, keeled, lower glume 1-veined, upper glume 1–3-veined; floret callus small, pubescent to conspicuously bearded; lemmas lanceolate to oblong, hyaline to shiny cartilaginous, back rounded, finely 4-veined (5th midvein extended into awn), glabrous, awned from near base or in lower half, apex membranous, broad, 4-toothed or denticulately truncate; awn straight or weakly geniculate, usually not exserted from spikelet; palea hyaline, subequal to lemma. Ovary glabrous. Caryopsis with solid endosperm.
About 40 species: temperate and cold regions of the world; three species in China.
(Authors: Wu Zhenlan (吴珍兰); Sylvia M. Phillips)