Oenothera linifolia |
Oenothera elata |
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threadleaf evening-primrose, threadleaf sundrop |
evening primrose, Hooker's evening-primrose, western evening primrose |
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Habit | Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. | 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. | ||||
Stems | unbranched or with many ascending branches arising near base, erect, 10–50 cm. |
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. |
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Leaves | in a basal rosette and cauline, basal 1–2(–4) × 0.2–0.6 cm, petiole 0.2–1(–1.5) cm, blade ovate to obovate or narrowly elliptic; cauline 1–4 × less than 0.1 cm, sessile, blade linear or filiform. |
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. |
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Inflorescences | erect, unbranched. |
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Flowers | usually 1–3 opening per day near sunrise; buds without free tips; sepals 1.5–2 mm; petals bright yellow, fading pink, obcordate to obovate, 3–5(–7) mm; filaments 1–2 mm, anthers 0.5–1 mm; style 1–2 mm, stigma surrounded by anthers at anthesis. |
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. |
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Capsules | ellipsoid-rhombic to subglobose, 4-angled, 4–6(–10) × 1.5–3 mm, stipe 0–4 mm, valve midrib raised at distal end, indehiscent or tardily dehiscent distally; sessile. |
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. |
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Seeds | clustered in each locule, ovoid, surface minutely papillose, 1 × 0.5 mm. |
1–1.9 × 0.6–1.2 mm. |
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2n | = 14. |
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Oenothera linifolia |
Oenothera elata |
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Phenology | Flowering Apr–Jun(–Aug). | |||||
Habitat | Prairies, open woodlands, open rocky and sandy sites, roadsides. | |||||
Elevation | 0–400 m. (0–1300 ft.) | |||||
Distribution |
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX
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w United States; c United States; Mexico; Central America
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Discussion | Kneiffia linearifolia Spach (1835) is an illegitimate name based on Oenothera linifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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Key |
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Source | FNA vol. 10. | FNA vol. 10. | ||||
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Peniophyllum | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Oenothera > subsect. Oenothera | ||||
Sibling taxa | ||||||
Subordinate taxa | ||||||
Synonyms | Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium | |||||
Name authority | Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) | Kunth in A. von Humboldt et al.: Nov. Gen. Sp. 6(fol.): 72; 6(qto.): 90. (1823) | ||||
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