Description from Flora of China
Asperella Humboldt (1790), not Asprella Schreber (1789).
Plants perennial, with short or creeping rhizomes. Culms usually erect. Leaf sheath of cauline leaves split almost to base; auricles crescent-shaped; ligule leathery-membranous. Spike erect or nodding, slender; rachis not disarticulating at nodes. Spikelets (1 or)2 per node, with 1–3 (4 in H. coreana) florets, distal floret usually sterile; rachilla disarticulating above glumes. Glumes usually weakly developed or sometimes absent (9–10 mm in H. coreana), subulate or linear-setiform, not keeled (keeled in H. coreana), scabrous. Lemma lanceolate, subleathery, 5–7-veined, without distinct keel, usually awned; callus subobtuse. Palea 2-keeled, ± ciliate along keels. Lodicules broadly lanceolate, margin ciliate. Caryopsis narrow, slightly furrowed, apex hairy. x = 7.
About ten species: mainly in warm-temperate regions of Asia and North America; four species (one endemic) in China.