Elymus is a genus of perennial plants with approximately 150 species[5] in the grass family, related to rye, wheat, and other widely grown cereal grains.

[6] Elymus is a cosmopolitan genus, represented by species across all continents of the world.

[7] Common names include couch grass, wildrye and wheatgrass.

[8][9][10][11] As of 2024[update], Plants of the World Online accepted 173 species and 19 hybrids:[12] Elymus multisetus (J.G.Sm.)

Burtt Davy Many species once considered members of Elymus are now regarded as better suited to other genera: Agropyron, Anthosachne, Brachypodium, Cenchrus, Crithopsis, Heteranthelium, Jouvea, Kengyilia, Leymus, Psathyrostachys, Stenostachys, Taeniatherum, Thinopyrum etc.