Achnatherum is a genus of plants which includes several species of needlegrass. Several needlegrass species have been switched between Achnatherum and genus Stipa; taxonomy between the two closely related genera is still uncertain.
Achnatherum hymenoides was useful as a food source to Native Americans. Achnatherum brachychaetum is best known as a noxious weed.
Species
19 species recognized by Plants of the World Online as of July 2023:
Species previously included in Achnatherum:
Achnatherum acutum (Swallen) Valdés-Reyna & Barkworth
Achnatherum aridum (M.E.Jones) Barkworth - Mormon needlegrass
Achnatherum bloomeri (Boland.) Barkworth - Bloomer's ricegrass
Achnatherum bromoides (L.) P. Beauv. Achnatherum brachychaetum (Godr.) Barkworth - punagrass Achnatherum capense (L.) P. Beauv. Achnatherum caragana (Trin. & Rupr.) Nevski Achnatherum caudatum (Trin.) S. L. W. Jacobs & J. Everett - Chilean ricegrass Achnatherum clandestinum (Hack.) Barkworth - Mexican ricegrass Achnatherum contractum (B.L. Johnson) Barkworth - contracted ricegrass Achnatherum coronatum (Thurb.) Barkworth - crested needlegrass Achnatherum curvifolium (Swallen) Barkworth - Guadalupe ricegrass Achnatherum diegoense (Swallen) Barkworth - San Diego needlegrass Achnatherum duthiei (Hook.f.) P.C. Kuo & S.L. Lu Achnatherum editorum (E. Fourn.) Valdés-Reyna & Barkworth Achnatherum eminens (Cav.) Barkworth - southwestern needlegrass Achnatherum hendersonii (Vasey) Barkworth - Henderson's needlegrass Achnatherum hymenoides (Oryzopsis hymenoides) Ricker ex Piper - Indian ricegrass Achnatherum latiglume (Swallen) Barkworth - wide-glumed needlegrass Achnatherum lemmonii (Vasey) Barkworth - Lemmon's needlegrass Achnatherum lettermanii (Vasey) Barkworth - Letterman's needlegrass Achnatherum lobatum (Swallen) Barkworth - lobed needlegrass Achnatherum nelsonii (Scribn.) Barkworth - Nelson's needlegrass, Dore's needlegrass Achnatherum nevadense (B.L. Johnson) Barkworth - Nevada needlegrass Achnatherum occidentale (Thurb.) Barkworth - western needlegrass Achnatherum parishii (Vasey) Barkworth - Parish's needlegrass Achnatherum perplexum Hoge & Barkworth - perplexing needlegrass Achnatherum pinetorum (M.E. Jones) Barkworth - pinewoods needlegrass Achnatherum richardsonii (Link) Barkworth - Richardson's needlegrass Achnatherum robustum (Vasey) Barkworth - sleepygrass Achnatherum roshevitzii Mussajev - Roshevich's achnatherum Achnatherum scribneri (Vasey) Barkworth - Scribner needlegrass Achnatherum speciosum Trin. & Rupr. - desert needlegrass Achnatherum splendens (Trin.) Nevski Achnatherum stillmanii (Bol.) Barkworth - Stillman's needlegrass Achnatherum thurberianum (Piper) Barkworth - Thurber's needlegrass Achnatherum swallenii (C.L. Hitchc. & Spellenb.) Barkworth - Swallen's needlegrass Achnatherum webberi (Thurb.) Barkworth - Webber needlegrass
References
CRC World Dictionary of Grasses - Common Names, Scientific Names, Eponyms, Synonyms, and Etymology - Volume I (A - D), by Umberto Quattrocchi,