Eriocoma occidentalis (western needlegrass)

Plate 1 figs. a–h · 8 separate observations

Eriocoma occidentalis, photographed by Tim Messick — fig. a Tim Messick, CC BY 4.0 / 2021-08-26 / obs. 155212146

Eriocoma occidentalis, photographed by Matt Lavin — fig. b Matt Lavin, CC BY 4.0 / obs. 154480138

Eriocoma occidentalis, photographed by Matt Berger — fig. d Matt Berger, CC BY 4.0 / obs. 148962119

Eriocoma occidentalis, photographed by Alan Weakley — fig. f Alan Weakley, CC0 1.0 / obs. 50329128

Every figure is a research-grade observation under CC0, CC BY or CC BY-SA, rehosted with the photographer’s name, the licence and the observation it came from. Photographs under a NonCommercial licence are excluded from this site and are never stored, which costs us a great many pictures and is not negotiable.

The specimen a real sheet, in a real collection

Herbarium: Smithsonian, US National Herbarium
Accession: US 1838574
Filed as: Eriocoma occidentalis subsp. occidentalis
Det. by: Poaceae Reorganization Project
Collected: H. L. Mason 1940-08-01
Origin: US
The sheet: View the digitised specimen (CC0 1.0)

A real pressed plant, in a real collection, under the accession number above. Not an illustration of one. The holding institution does not serve this sheet’s image to third parties, so there is no photograph here. The record is real and the link goes to it. Where we hold no openly licensed sheet for a species this section is simply absent, and where a sheet never recorded who determined it, that field stays empty rather than being filled in. Roughly half of all herbarium sheets never recorded a determiner, which is ordinary.

Native range 13 botanical countries

Native distribution of Eriocoma occidentalis, after Kew’s World Checklist of Vascular Plants. Introduced, extinct and doubtful records are excluded, so this is where the plant is from, not everywhere it now grows.

Region	TDWG code	Continent
Alberta	ABT	NORTHERN AMERICA
Arizona	ARI
British Columbia	BRC
California	CAL
Colorado	COL
Idaho	IDA
Mexico Northeast	MXE
Montana	MNT
Nevada	NEV
Oregon	ORE
Utah	UTA
Washington	WAS
Wyoming	WYO

Region boundaries approximated from Natural Earth (public domain) and mapped to TDWG World Geographical Scheme for Recording Plant Distributions (WGSRPD) level-3 botanical countries (Brummitt 2001). Indicative, not the official WGSRPD geometry.

Also published as 15 synonyms

A synonym is not an error. It is a record of botanists disagreeing, in print, about where this plant belongs. Each of these was somebody’s considered answer.

Achnatherum nelsonii subsp. longiaristatum (Barkworth & J.R.Maze) Barkworth
Achnatherum occidentale (Thurb. ex S.Watson) Barkworth
Achnatherum occidentale subsp. californicum (Merr. & Burtt Davy) Barkworth
Achnatherum occidentale subsp. pubescens (Vasey) Barkworth
Stipa californica Merr. & Burtt Davy
Stipa elmeri Piper & Brodie
Stipa nelsonii var. longiaristata Barkworth & J.R.Maze
Stipa occidentalis Thurb. ex S.Watson
Stipa occidentalis var. californica (Merr. & Burtt Davy) C.L.Hitchc.
Stipa occidentalis var. montana Merr. & Burtt Davy
Stipa occidentalis var. pubescens (Vasey) J.R.Maze, Roy L.Taylor & MacBryde
Stipa oregonensis Scribn.
Stipa stricta Vasey
Stipa stricta var. sparsiflora Vasey
Stipa viridula var. pubescens Vasey

Sourcesevery claim on this page

World Flora Online Plant List. accepted name, authority, classification. CC0. Retrieved 2026-07-12.
iNaturalist. photographs and flowering annotations, CC0 / CC BY / CC BY-SA only. per photograph. Retrieved 2026-06-27.
USDA PLANTS Database. common name, checklist symbol ACOC3. public domain. Retrieved 2026-07-13.
Kew, World Checklist of Vascular Plants (WCVP v16). native distribution by TDWG level-3 botanical country, and life form. CC BY 3.0. Retrieved 2026-06-04.

We publish what we can source and we say so when we cannot. This page has no care advice and no toxicity claim, because we do not yet have those from a source we can cite.