Oenothera spachiana |
Oenothera pubescens |
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spach's evening primrose |
pubescent evening primrose, silky evening primrose, South American evening-primrose |
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Habit | Herbs annual, densely strigillose; from a sparsely branched taproot. | Herbs annual or biennial, densely to sparsely strigillose, sometimes also villous and glandular puberulent distally; from a taproot. |
Stems | erect, usually unbranched or with few ascending branches, 10–30(–45) cm. |
unbranched or with branched central stem and ascending to decumbent lateral branches arising from rosette, 5–50(–80) cm. |
Leaves | in a basal rosette and cauline, basal 2–5 × 0.5–1.5 cm, petiole 0.5–2 cm, blade oblanceolate to elliptic, margins subentire; cauline 3–6 × 0.2–0.6 cm, petiole 0.2–0.6(–1.5) cm, blade narrowly lanceolate to linear, margins subentire. |
in a basal rosette and cauline, basal 5–14 × 0.5–2.5 cm, cauline 2–8 × 0.5–2.5 cm; blade narrowly oblanceolate to narrowly elliptic or narrowly oblong, margins usually dentate to deeply lobed; bracts spreading, flat. |
Inflorescences | erect, flowers in leaf axils in distal 1/2 of plant. |
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Flowers | opening near sunrise; buds with free tips to 1 mm, erect to spreading; floral tube 4–10 mm; sepals 4–8 mm; petals pale yellow, fading pale pink, 5–14 mm; filaments 3–7 mm, anthers 2–4 mm, pollen 85–100% fertile; style 3–7 mm, stigma surrounded by anthers. |
usually 1 opening per day near sunset; buds with free tips erect, 0.1–1 mm; floral tube erect, becoming recurved and nodding, then erect again just before anthesis, 15–50 mm; sepals 5–25 mm; petals yellow, fading reddish orange, broadly obovate to obcordate, 5–25(–35) mm; filaments 6–18 mm, anthers (2–)3–9 mm, pollen ca. 50% fertile; style 20–60 mm, stigma surrounded by or slightly exserted beyond anthers at anthesis. |
Capsules | broadly clavate, 4-angled, 5–15 × 3–5 mm, stipe 2–5 mm; sessile. |
cylindrical, sometimes slightly enlarged distally, 20–45 ×2–4 mm. |
Seeds | 1 × 0.5 mm. |
brown, sometimes dark-flecked, 0.9–1.5 × 0.6–1 mm. |
2n | = 14. |
= 14. |
Oenothera spachiana |
Oenothera pubescens |
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Phenology | Flowering Mar–May. | Flowering (Feb–)Apr–Sep(–Oct). |
Habitat | Prairies, open roadsides, sandy places. | Open sites in montane habitats. |
Elevation | 10–200 m. (0–700 ft.) | (1300–)1500–2500(–3100) m. ((4300–)4900–8200(–10200) ft.) |
Distribution |
AL; AR; LA; MS; OK; TX |
AZ; NM; TX; Mexico; West Indies; Central America (Guatemala); South America (Colombia, Ecuador, Peru)
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Discussion | G. B. Straley (1977) determined Oenothera spachiana to be self-compatible and autogamous. Collections outside the native range of O. spachiana have been made as a ballast weed in Camden County, New Jersey. Oenothera drummondii (Spach) Walpers (1843), not Hooker (1834) is a later homonym and pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera pubescens 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). Oenothera pubescens has been collected once in California in 1884 (Newberry Springs, San Bernardino County), where it was temporarily introduced or a natural occurrence that was extirpated. Collections from west Texas (Brewster, Jeff Davis, and Presidio counties) have been made since 1990 and a few others collected earlier were misidentified as O. laciniata. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | Blennoderma drummondii, Kneiffia spachiana, O. uncinata | Anogra amplexicaulis, O. amplexicaulis, O. laciniata subsp. pubescens, Var. o. var. o., O. nyctaginiifolia, O. stuebelii, Raimannia colimae, R. confusa |
Name authority | Torrey & A. Gray: Fl. N. Amer. 1: 498. (1840) | Willdenow ex Sprengel: Syst. Veg. 2: 229. (1825) |
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