Eriocoma is a genus of grasses in the family Poaceae (order Poales), comprising 27 accepted species native to western and central North America. The genus ranges from Alaska and the Yukon in the north through western and central Canada, across the western and central United States, and into northern Mexico. Species formerly placed in Achnatherum and related genera were transferred to Eriocoma following molecular phylogenetic revisions; the reclassification was published by Romaschenko and colleagues.
Members of Eriocoma are perennial bunchgrasses adapted to arid and semi-arid habitats, including sagebrush steppe, open woodlands, and mountain slopes. The genus is ecologically significant in western North American rangeland communities. Widely distributed species such as Eriocoma hymenoides — known as Indian ricegrass — grow from the Yukon south through the Great Basin and onto the Colorado Plateau, while other species have narrow endemic ranges, such as Eriocoma arnowiae, restricted to Utah. Several species have economic and cultural importance: Indian ricegrass (E. hymenoides) was a staple food grain for many Indigenous peoples of the Southwest.
Distribution
Eriocoma species are native to western and central North America, with the range extending from Alaska and the Yukon through western and central Canada, across the western and central United States, and into northern Mexico. Individual species vary greatly in range: some, such as Eriocoma hymenoides and Eriocoma richardsonii, span thousands of kilometres from subarctic Canada to the American Southwest, while others are restricted to single states or narrow mountain ranges.
Taxonomy Notes
Eriocoma belongs to the tribe Stipeae within the grass family Poaceae. Many of its species were previously classified under Achnatherum, Stipa, or related genera; the current circumscription and species transfers were formalised by Romaschenko, Peterson, and Soreng. GBIF recognises 26 descendant taxa under the accepted genus name Eriocoma.
