Oenothera elata |
Oenothera humifusa |
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evening primrose, Hooker's evening-primrose, western evening primrose |
seabeach evening-primrose |
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Habit | Herbs biennial or short-lived perennial, densely strigillose and either sparsely or moderately villous, with appressed or spreading hairs (sometimes with red-pustulate bases), distally sometimes also glandular puberulent. | Herbs annual or short-lived perennial, densely strigillose, sometimes also villous, also becoming glandular puberulent distally. | ||||
Stems | erect, green, flushed with red proximally or red throughout, unbranched or branches obliquely arising from rosette and secondary branches arising from main stem, 30–250 cm. |
erect to decumbent, much branched, 10–50(–90) cm. |
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Leaves | in a basal rosette and cauline, basal 10–43 × 1.2–4(–6) cm, cauline 4–25 × 1–2.5(–4) cm; blade dull green to grayish green, rarely red, narrowly oblanceolate or oblanceolate to narrowly elliptic or narrowly lanceolate, margins usually flat, rarely undulate, bluntly dentate or subentire, teeth sometimes widely spaced, proximal blades sometimes sinuate-dentate toward base; bracts persistent. |
in a basal rosette and cauline, basal 4–8 × 0.7–1 cm, cauline 1–7 × 0.3–1.5 cm; blade usually grayish green, narrowly oblong to narrowly elliptic or narrowly obovate, margins remotely shallowly dentate to subentire; bracts spreading, flat. |
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Inflorescences | erect, unbranched. |
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Flowers | opening near sunset; buds erect, 6–10 mm diam., with free tips terminal, erect, 1–7 mm; floral tube (20–)30–45(–50) mm; sepals yellowish green, red-striped or strongly flushed with red, 27–50 mm; petals yellow to pale yellow, fading orange or pale yellow, very broadly obcordate, (25–)30–47(–55) mm; filaments 17–25 mm, anthers 8–23 mm, pollen 90–100% fertile; style 50–90 mm, stigma exserted beyond anthers at anthesis. |
usually 1 opening per day near sunset; buds erect, with free tips erect and appressed or slightly spreading, 0.5–2 mm; floral tube 15–35 mm; sepals3–11 mm; petals yellow, very broadly obovate or obcordate, 4.5–16 mm; filaments 4–11 mm, anthers 2–5.5 mm, pollen ca. 50% fertile; style 23–45 mm, stigma surrounded by anthers at anthesis. |
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Capsules | erect or slightly spreading, dull green or gray-green when dry, narrowly lanceoloid, 20–65 × 4–7 mm, free tips of valves 0.5–2.5 mm. |
cylindrical, sometimes slightly enlarged toward apex, 15–45 × 2–3 mm. |
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Seeds | 1–1.9 × 0.6–1.2 mm. |
usually ellipsoid to broadly ellipsoid, rarely subglobose, 1–2 × 0.5–0.9 mm. |
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2n | = 14. |
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Oenothera elata |
Oenothera humifusa |
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Phenology | Flowering Apr–Nov. | |||||
Habitat | Dunes, open sandy places along or near Atlantic coast. | |||||
Elevation | 0–10 m. (0–0 ft.) | |||||
Distribution |
w United States; c United States; Mexico; Central America
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AL; DE; FL; GA; LA; MD; MS; NC; NJ; PA; SC; VA; Dunes; open sandy places along or near Atlantic coast; West Indies (Cuba); Bermuda
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Discussion | Subspecies 3 (2 in the flora). Subspecies elata differs in anthers 7–12 mm, fewer or no pustulate-based hairs, and generally smaller flowers and habit. It ranges from the highlands of central Mexico, including Guanajuato, Hidalgo, México, Michoacán, Puebla, Querétaro, and Veracruz, south to Guatemala, El Salvador, Costa Rica, and Panama. Oenothera elata has plastome I and a AA genome composition. Onagra kunthiana Spach is a superfluous name that pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera humifusa is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich and W. L. Wagner 1988). The inland collection from Iredell County, North Carolina, presumably represents an introduction. There are two geographically separated morphological forms of O. humifusa. Plants of one form are somewhat decumbent, with subentire cauline leaves and bracts; this form occurs in the southern part of the range. The other form is more upright, with more deeply divided leaves; it occurs from North Carolina northward. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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Key |
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Source | FNA vol. 10. | FNA vol. 10. | ||||
Parent taxa | ||||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | O. niveifolia, O. sinuata var. humifusa, Raimannia humifusa | |||||
Name authority | Kunth in A. von Humboldt et al.: Nov. Gen. Sp. 6(fol.): 72; 6(qto.): 90. (1823) | Nuttall: Gen. N. Amer. Pl. 1: 245. (1818) | ||||
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