Oenothera deltoides (birdcage evening primrose)

Plate 1 figs. a–h · 8 separate observations

Oenothera deltoides, photographed by zancat — fig. a zancat, CC BY 4.0 / 2021-12-09 / obs. 171907731

Oenothera deltoides, photographed by Tim Messick — fig. b Tim Messick, CC BY 4.0 / obs. 153955637

Oenothera deltoides, photographed by Bob Miller — fig. c Bob Miller, CC BY 4.0 / obs. 116257271

Oenothera deltoides, photographed by Leah Gardner — fig. d Leah Gardner, CC0 1.0 / obs. 94227134

Oenothera deltoides, photographed by P Holroyd — fig. e P Holroyd, CC BY 4.0 / obs. 61354823

Oenothera deltoides, photographed by Gerard Walschlager — fig. g Gerard Walschlager, CC BY 4.0 / obs. 43504901

Oenothera deltoides, photographed by Casey H. Richart — fig. h Casey H. Richart, CC BY 4.0 / obs. 32822808

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.

Native range 6 botanical countries

Native distribution of Oenothera deltoides, 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
Arizona	ARI	NORTHERN AMERICA
California	CAL
Mexico Northwest	MXN
Nevada	NEV
Oregon	ORE
Utah	UTA

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.

Flowering 2,100 in flower of 2,451 examined

79%

84%

96%

89%

100%

86%

83%

11%

69%

75%

Proportion of examined Oenothera deltoides in flower, by month
Month	In flower	Examined	Share	95% interval
Jan	201	253	79%	74% to 84%
Feb	457	544	84%	81% to 87%
Mar	874	911	96%	94% to 97%
Apr	168	189	89%	84% to 93%
May	48	48	100%	93% to 100%
Jun	18	18	100%	82% to 100%
Jul	12	14	86%	60% to 96%
Aug	5	6	83%	44% to 97%
Sep	1	9	11%	2% to 44%
Oct	2	19	11%	3% to 31%
Nov	159	232	69%	62% to 74%
Dec	155	208	75%	68% to 80%

Peak flowering in May. Each bar is the share of Oenothera deltoides observations in which someone actually recorded the reproductive state and found the plant in flower, not the raw number of flowering records. That distinction matters: people observe plants far more in spring than in winter, so a bare count of flowering records partly measures when people go outside. Dividing by the number examined removes that. 2,100 of 2,451 examined observations were in flower, every one of them research grade. The whisker on each bar is a 95% Wilson interval. This is still a global aggregate and not a forecast for your garden: the same species flowers on different dates in different hemispheres. Where a species has fewer than 30 flowering records we do not draw this chart at all. Computed from 10.15468/dl.cgje2x.

Also published as 18 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.

Anogra deltoidea (Torr. & Frém.) Small
Anogra simplex Small
Oenothera albicaulis var. decumbens S.Watson
Oenothera ambigua S.Watson
Oenothera deltoides f. floccosa Munz
Oenothera deltoides f. glabrata Munz
Oenothera deltoides subsp. deltoides
Oenothera deltoides var. ambigua Munz
Oenothera deltoides var. cineracea Munz
Oenothera deltoides var. cognata (Jeps.) Munz
Oenothera deltoides var. decumbens (S.Watson) Munz
Oenothera deltoides var. howellii Munz
Oenothera deltoides var. piperi Munz
Oenothera deltoides var. typica Munz
Oenothera kleinii W.L.Wagner & S.W.Mill.
Oenothera simplex (Small) Tidestr.
Oenothera trichocalyx var. cineracea Jeps.
Oenothera trichocalyx var. cognata Jeps.

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.
Wikidata. common name (P1843), joined on the World Flora Online identifier (P7715). CC0. 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.