Oenothera albinervis R. R. Gates; O. bauri Boedijn; O. biennis Linnaeus var. canescens Torrey & A. Gray; O. canovertex Hudziok; O. canovirens E. S. Steele; O. cockerellii Bartlett ex de Vries; O. depressa Greene; O. erosa Lehmann; O. hookeri Torrey &A. Gray var. parviflora R. R. Gates; O. hungarica (Borbás) Borbás; O. muricata Linnaeus var. canescens (Torrey & A. Gray) B. L. Robinson; O. muricata subsp. hungarica (Borbás) Soó; O. parviflora Linnaeus var. canescens (Torrey & A. Gray) Farwell; O. renneri H. Scholz; O. strigosa (Rydberg) Mackenzie & Bush var. albinervis (R. R. Gates) R. R. Gates; O. strigosa subsp. canovirens (E. S. Steele) Munz; O. strigosa var. cockerellii (Bartlett ex de Vries) R. R. Gates; O. strigosa subsp. hungarica (Borbás) Á. Löve & D. Löve; O. velutinifolia Hudziok; Onagra depressa (Greene) Small; O. hungarica Borbás

Herbs dull green to grayish green, densely strigillose, sometimes also sparsely villous with appressed or subappressed hairs, these without or with red or green pustules, rarely glandular puberulent distally. Leaves grayish green to dull green, blade margins conspicuously dentate, sometimes sinuate-dentate proximally, venation prominent, especially abaxially, usually pale green, rarely red. Inflorescences relatively dense, apex truncate, internodes in fruit conspicuously shorter than capsules. Flowers: sepals green to yellowish green. 2n = 14.

Flowering Jul–Aug(–Sep). Open, often wet sites, streamsides, fields, roadsides; 30–1500(–1700) m; Alta., B.C., Man., N.B., N.S., Ont., Que., Sask.; Ala., Ark., Colo., Conn., Ga., Ill., Ind., Iowa, Kans., Ky., Maine, Md., Mass., Mich., Minn., Miss., Mo., Mont., Nebr., N.H., N.J., N.Y., N.C., N.Dak., Ohio, Okla., Pa., S.Dak., Tenn., Tex., Vt., Va., W.Va., Wis., Wyo.; introduced in s South America, Europe, Asia, s Africa.

Subspecies villosa appears to be largely a taxon of the Great Plains that has subsequently, both naturally and with human assistance, spread to the north and east, primarily in historical times. It grows in a variety of habitats, primarily prairies, along streams or lakes, open woodlands, old fields, and other disturbed sites, and is widely naturalized in Asia, Europe, southern South America, and South Africa.

Oenothera strigosa (Rydberg) Mackenzie & Bush var. depressa (Greene) R. R. Gates is an illegitimate name, as is O. salicifolia Desfontaines ex G. Don 1837, not Lehmann 1824 and not Desfontaines ex Seringe 1825, and these names pertain here.