This widespread western species occurs as waifs in eastern states, or perhaps locally adventive plants along railroads and similar sites. It is a rhizomatous octoploid (2n = 56), probably derived from hybridization of Elymus lanceolatus (Scribn. & J.G. Sm.) Gould with Leymus triticoides (Buckl.) Pilg., and its generic name has been uncertain (FNA 24).