Onagra strigosa Rydberg, Mem. New York Bot. Gard. 1: 278. 1900; Oenothera biennis Linnaeus var. strigosa (Rydberg) Cronquist; O. cheradophila Bartlett; O. procera Wooton & Standley; O. strigosa (Rydberg) Mackenzie & Bush subsp. cheradophila (Bartlett) Munz; O. strigosa var. cheradophila (Bartlett) R. R. Gates; O. strigosa var. procera (Wooton & Standley) R. R. Gates; O. subulifera Rydberg; O. villosa subsp. cheradophila (Bartlett) W. Dietrich & P. H. Raven; O. villosa var. strigosa (Rydberg) Dorn; Onagra biennis (Linnaeus) Scopoli var. strigosa (Rydberg) Piper; O. strigosa var. subulata Rydberg; Usoricum strigosum (Rydberg) Lunell

Herbs flushed with red, at least proximally, often red throughout, strigillose, rarely exclusively so, usually also villous with erect to ascending or subappressed red-pustulate hairs, and glandular puberulent, at least distally. Leaves green to dull green, blade margins usually denticulate or subentire, sometimes moderately dentate, venation not prominent. Inflorescences relatively open, apex obtuse, internodes in fruit usually equal to or longer than capsule. Flowers: sepals red-striped or flushed with red. 2n = 14.

Flowering Jun–Sep. Open, often wet sites, stream­sides, fields, roadsides; 30–3200 m; Alta., B.C., Man., N.W.T., Ont., Sask.; Ariz., Calif., Colo., Idaho, Mich., Minn., Mont., Nebr., Nev., N.Mex., N.Dak., Oreg., S.Dak., Utah, Wash., Wis., Wyo.

Subspecies strigosa occurs primarily in the Pacific Northwest southeast through the Rocky Mountains, and is found in mostly montane and foothill habitats. It has not spread much, if at all, outside of its native range.

Oenothera strigosa (Rydberg) Mackenzie & Bush is an illegitimate later homonym that pertains here; O. rydbergii House and O. strigosa (Rydberg) Mackenzie & Bush var. subulifera R. R. Gates also pertain here and are superfluous names.