Annual or perennial. Leaf blades linear, flat or rolled, often auriculate; ligule membranous. Inflorescence a single, stiff, 2-sided raceme, spikelets arranged edgeways on, alternate in 2 opposite rows, their inner edges sunk in hollows of the tough rachis. Spikelets laterally compressed, florets several to many, uppermost florets reduced, disarticulating below each floret; glumes leathery; lower glume suppressed except in terminal spikelet and there similar to upper; upper glume abaxial, narrow, persistent, shorter than lemmas to as long as spikelet; lemmas membranous to leathery, rounded on back, 5–9-veined, with or without a subterminal awn; palea usually equal to lemma. Caryopsis tightly enclosed by hardened lemma and palea; hilum linear.

Most species are good forage grasses. Lolium is a difficult genus taxonomically as all the species are more or less interfertile and consequently intergrade. The individual species are also very variable. Most will hybridize with Festuca arundinacea and its allies, and the resulting hybrids have the nothogeneric name ×Festulolium Ascherson & Graebner.

About eight species: temperate N Africa, Asia, and Europe, especially the Mediterranean region; now widely introduced or adventive elsewhere; six species (at least four introduced) in China.

(Authors: Liu Liang (刘亮); Sylvia M. Phillips)