Oenothera nutans |
Oenothera fruticosa |
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nodding evening-primrose |
narrow-leaf evening-primrose |
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Habit | Herbs biennial, often appearing glabrous to naked eye, usually strigillose and sparsely to moderately villous proximal to inflorescence, hairs translucent and with or without pustules, pustules not red (in fresh material), inflorescence glabrous, glandular puberulent, or strigillose and glandular puberulent. | Herbs perennial, moderately to densely strigillose and/or villous, glandular puberulent, or glabrous; from fibrous roots, not or rarely producing rhizomes. | ||||
Stems | erect, red on proximal parts, green on distal ones, rarely red throughout, unbranched or with branches obliquely arising from rosette and secondary branches arising from main stem, 30–200 cm. |
erect to decumbent, branched or unbranched, (10–)30–80 cm. |
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Leaves | in a basal rosette and cauline, basal 10–32 × 3–7 cm, cauline 6–20 × 2–8 cm; blade green to pale green, narrowly oblanceolate to narrowly obovate, or narrowly elliptic, sometimes lanceolate distally, margins usually flat, rarely undulate, bluntly dentate, teeth widely spaced, sometimes sinuate-dentate proximally; bracts caducous. |
in a basal rosette and cauline, rosette usually withered by anthesis, surfaces sometimes glaucous, especially abaxially, basal 3–12 × 0.5–3 cm, petiole 1–4 cm, blade oblanceolate to obovate, margins subentire, dentate, or denticulate, sometimes undulate; cauline 2–6(–11) × (0.1–)0.5–2(–5) cm, petiole 0.1–2(–6) cm, blade linear, lanceolate to oblanceolate, narrowly elliptic, or ovate, margins subentire or dentate or denticulate, sometimes undulate. |
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Inflorescences | erect, unbranched or with secondary branches just proximal to main one. |
usually erect, rarely nodding, flowers in axils of distalmost few nodes. |
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Flowers | opening near sunset; buds erect, 4–6 mm diam., with free tips terminal, erect, 1.5–6 mm; floral tube 30–43 mm; sepals yellowish green or flushed with red, 10–23 mm; petals yellow to pale yellow, fading pale yellowish white, very broadly obcordate, 14–25(–30) mm; filaments 10–25 mm, anthers 4–10 mm, pollen ca. 50% fertile; style 35–63 mm, stigma surrounded by anthers at anthesis. |
opening near sunrise; buds with free tips 0.5–8(–13) mm, connivent, sometimes spreading; floral tube 5–20 mm; sepals 5–20 mm; petals pale to bright yellow, fading pale pink, orangish pink, or yellow, (8–)15–25(–30) mm; filaments 5–15 mm, anthers 4–7 mm, pollen 85–100% fertile; style 12–20 mm, stigma exserted beyond anthers at anthesis. |
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Capsules | erect or slightly spreading, dull green when dry, narrowly lanceoloid to narrowly ovoid, 12–36 × 3–6 mm, free tips of valves 1–1.5 mm. |
clavate to oblong-clavate or oblong-ellipsoid, 4-angled to 4-winged, (5–)10–17(–20) × (2–)3–4(–6) mm, stipe 0.1–10 mm; sessile. |
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Seeds | 1–1.9 × 0.6–0.9 mm. |
1 × 0.5 mm. |
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2n | = 14. |
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Oenothera nutans |
Oenothera fruticosa |
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Phenology | Flowering Jun–Aug(–Sep). | |||||
Habitat | Open, often disturbed sites, stream beds, flood plains, slopes, margins of mixed deciduous forests, roadsides, old fields. | |||||
Elevation | (200–)400–1700 m. ((700–)1300–5600 ft.) | |||||
Distribution |
AL; AR; CT; DE; FL; GA; IN; KY; MA; MD; ME; MI; MO; NC; NH; NJ; NY; OH; PA; SC; TN; VA; VT; WV; ON |
e North America; c North America
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Discussion | Oenothera nutans is a PTH species and forms a ring of 14 chromosomes or a ring of 12 and 1 bivalent in meiosis, and is self-compatible and autogamous (W. Dietrich et al. 1997). It has plastome III and a BB genome composition. The disjunct occurrences of O. nutans in Arkansas and Missouri probably represent unintentional introductions by humans. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Subspecies 2 (2 in the flora). Oenothera fruticosa as delimited here is a polymorphic species. Previous classification of this group has undergone numerous reorganizations due to the difficulties in separating populations into discrete morphological taxa. In the past it has most frequently been treated as two species, O. fruticosa and O. tetragona Roth, often with a dozen or more infraspecific taxa recognized. The broad delimitation of G. B. Straley (1977) is followed here with one species consisting of two subspecies that appear to intergrade extensively across a wide area of overlap. Straley determined O. fruticosa to be self-incompatible and polyploid. (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. austromontana, O. biennis subsp. austromontana, O. biennis var. austromontana, O. biennis var. nutans | Kneiffia fruticosa | ||||
Name authority | G. F. Atkinson & Bartlett: Rhodora 15: 83. (1913) | Linnaeus: Sp. Pl. 1: 346. (1753) | ||||
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