Oenothera rosea |
Oenothera albicaulis |
|
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pink evening primrose, rose evening-primrose |
white-stem evening-primrose, whitest evening primrose, whitish evening primrose |
|
Habit | Herbs perennial, caulescent, strigillose and often also sparsely hirsute; from slender taproot. | Herbs winter-annual, densely strigillose, also sparsely villous; from a taproot. |
Stems | 1–several, ascending to decumbent, 7–65 cm. |
ascending to decumbent, 1–several from base, sometimes unbranched, erect or ascending, 5–30 cm. |
Leaves | in a basal rosette and cauline, basal 1–6 × 0.3–2 cm, blade narrowly elliptic to elliptic or ovate, margins subentire, weakly serrulate, or sinuate-pinnatifid; cauline 1–6 × 0.3–2 cm, blade narrowly elliptic to narrowly ovate, margins subentire or weakly serrulate, proximal ones sinuate-pinnatifid. |
in a basal rosette and cauline, 1.5–10 × 0.3–2.5 cm; blade oblanceolate to oblong, margins subentire or coarsely dentate or pinnatifid. |
Inflorescences | erect. |
|
Flowers | 1–3 opening per day near sunrise; buds with free tips 0.1–1 mm; floral tube 4–8 mm; sepals 6–12 mm; petals rose purple, fading darker, 4–12 mm; filaments 4–6 mm, anthers 2–3.5 mm, pollen 35–65% fertile; style 7–13.5 mm, stigma surrounded by anthers at anthesis. |
1–3 opening per day near sunset; buds nodding, weakly quadrangular, without free tips; floral tube 15–30 mm, mouth glabrous; sepals 15–30 mm; petals white, fading pink, usually obcordate, sometimes obovate, (15–)20–35(–40) mm; filaments 11–17 mm, anthers 6–10 mm; style 25–50 mm, stigma exserted beyond anthers at anthesis. |
Capsules | narrowly obovoid, 4–12 × 2–4 mm, apex attenuate to a sterile beak, proximal stipe 5–20 mm, gradually tapering to base, valve midrib prominent in distal part; sessile. |
ascending to erect, usually straight, sometimes curved, cylindrical, weakly 4-angled, 20–40 × 3–4 mm, dehiscent 1/2 their length; sessile. |
Seeds | narrowly obovoid, 0.5–0.9 × 0.3–0.5 mm. |
in 2 rows per locule, ellipsoid to subglobose, 0.8–1.5 × 0.5–0.9 mm, surface regularly pitted, pits in longitudinal lines. |
2n | = 14. |
= 14. |
Oenothera rosea |
Oenothera albicaulis |
|
Phenology | Flowering Mar–Sep. | Flowering (Feb–)Mar–Jun(–Dec). |
Habitat | tropical areas.. | Dry, usually sandy flats and slopes. |
Elevation | 10–600 m. (0–2000 ft.) | 1000–2300 m. (3300–7500 ft.) |
Distribution |
AZ; CA; TX; Mexico; Central America; West Indies; tropical areas [Introduced in South America (Argentina), Europe, Asia, s Africa, Atlantic Islands (Azores, Canary Islands)]
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AZ; CO; ID; KS; MT; ND; NE; NM; OK; SD; TX; UT; WY; Mexico (Chihuahua, Sonora)
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Discussion | Oenothera rosea is a PTH species, forming a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous. In the flora area, it is known from Cochise, Pima, and Santa Cruz counties in Arizona, Alameda, Los Angeles, Riverside, San Bernardino, San Diego, San Francisco, and Santa Barbara counties in California (primarily in urban areas), and from southern Texas. It is clearly of North American origin, since all of its close relatives are confined to North America, and has spread south along the Andes. It occurs at 500–3700 m in South America but generally at lower elevations in most areas. The name Hartmannia affinis Spach is illegitimate, being based on Oenothera virgata; H. gauroides Spach is also illegitimate, being based on O. rosea; O. purpurea Lamarck is a later homonym; these three names pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera albicaulis is self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). Oenothera albicaulis has been reported from southern Nevada, but documentation is needed of its occurrence there. Anogra pinnatifida Spach, Baumannia pinnatifida Spach, Oenothera pinnatifida Nuttall, O. purshiana Steudel, and O. purshii G. Don are illegitimate names that pertain here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Gaura epilobia, Godetia heuckii, Hartmannia rosea, H. rosea var. parvifolia, H. virgata, O. psycrophila, O. rosea var. parvifolia, O. rubra, O. virgata, Xylopleurum roseum | Anogra albicaulis, A. bradburiana, A. buffumii, A. confusa, A. ctenophylla, A. perplexa, O. albicaulis var. xanthosperma, O. ctenophylla, O. sinuata var. bicolor |
Name authority | L’Héritier ex Aiton: Hort. Kew. 2: 3. (1789) | Pursh: Fl. Amer. Sept. 2: 733. (1813) |
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