Great Basin Naturalist


Revision of the perennial genera of North American Triticeae requires recognition of seven new genera in the Intermountain Region: Elytrigia, Leymus, Psathyrostachys, Pseudoroegneria, Thinopyrum, and the hybrid genera × Elyleymus and × Pseudelymus. One previously recognized genus, Sitanion, is included in Elymus. Several new combinations are presented to accommodate the taxonomic changes. Elymus trachycaulus is treated as a widespread, polymorphic species with three subspecies in the region: subsp. trachycaulus, subsecundus, and latiglumis. Agropyron dasystachyum and A. albicans are treated as conspecific subspecies of Elymus lanceolatus. A key to the genera of the Triticeae occurring in the Intermountain Region is presented as well as keys and brief descriptions for those genera not included in, or substantially modified from, other regional treatments.