Oenothera cespitosa |
Oenothera spachiana |
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fragrant evening-primrose, tuft evening-primrose |
spach's evening primrose |
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Habit | Herbs perennial, acaulescent or caulescent, usually hirsute or villous, usually also glandular puberulent, or exclusively strigillose, rarely glabrous; from stout taproot, sometimes lateral roots producing adventitious shoots. | Herbs annual, densely strigillose; from a sparsely branched taproot. | ||||||||||||||||||||||||||||
Stems | (when present), usually ascending or decumbent, unbranched or branched from near base, 0–40 cm. |
erect, usually unbranched or with few ascending branches, 10–30(–45) cm. |
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Leaves | 1.7–26(–36) × (0.3–)0.5–4.5(–6.5) cm; petiole (0.2–)1.7–11(–14) cm; blade usually oblanceolate to rhombic or spatulate, rarely elliptic, obovate, lanceolate, or linear-oblanceolate, margins irregularly sinuate-dentate, serrate, pinnatifid, lobed, or subentire, apex usually acute to rounded, rarely acuminate. |
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. |
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Inflorescences | erect, flowers in leaf axils in distal 1/2 of plant. |
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Flowers | 1–4(–6) per stem opening per day near sunset, with moderate to strong sweet scent with a rubbery background scent; buds usually erect, rarely recurved (during early development); floral tube (20–)40–140(–165) mm; sepals (15–)18–45(–54) mm; petals white, fading rose or rose pink to dark or deep rose purple, or pink to pale or light rose, or lavender, obovate or obcordate, (16–)20–50(–60) mm; filaments (6–)10–30(–35) mm, anthers (6–)9–17(–20) mm; style (45–)60–180(–185) mm, stigma exserted beyond anthers at anthesis. |
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. |
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Capsules | straight, curved, falcate, or sigmoid, usually cylindrical to lanceoloid or ellipsoid, sometimes ovoid, usually obtusely 4-angled, (10–)13–50(–68) × 4–9 mm, tapering to a sterile beak 6–8 mm, valve margins with rows of distinct tubercles to sinuate or nearly smooth ridges, dehiscent 1/3–7/8 their length; pedicel (0–)1–40(–55) mm. |
broadly clavate, 4-angled, 5–15 × 3–5 mm, stipe 2–5 mm; sessile. |
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Seeds | numerous in 1 or 2 rows per locule, usually obovoid, oblong, or triangular, rarely suborbicular, 2.1–3.9 × 1–2.6 mm, embryo 1/5–2/3 of seed volume, surface papillose, reticulate or rarely irregularly roughened; seed collar sealed by a thin membrane, this flat or depressed into raphial cavity, when depressed often splitting, becoming separated from seed collar. |
1 × 0.5 mm. |
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2n | = 14, 28. |
= 14. |
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Oenothera cespitosa |
Oenothera spachiana |
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Phenology | Flowering Mar–May. | |||||||||||||||||||||||||||||
Habitat | Prairies, open roadsides, sandy places. | |||||||||||||||||||||||||||||
Elevation | 10–200 m. (0–700 ft.) | |||||||||||||||||||||||||||||
Distribution |
w North America; nw Mexico
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AL; AR; LA; MS; OK; TX |
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Discussion | Subspecies 5 (5 in the flora). Oenothera cespitosa occurs in a wide array of habitats, from grassland, desert scrub, pinyon-juniper woodland, or Arizona chaparral to montane conifer forests, rarely at timberline, at elevations from (450–)800–3370 m. Oenothera cespitosa is self-incompatible (W. L. Wagner et al. 1985; Wagner 2005). Pachylophus nuttallii Spach is an illegitimate name that pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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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. Pachylophus | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Kneiffia | ||||||||||||||||||||||||||||
Sibling taxa | ||||||||||||||||||||||||||||||
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Synonyms | Pachylophus cespitosus | Blennoderma drummondii, Kneiffia spachiana, O. uncinata | ||||||||||||||||||||||||||||
Name authority | Nuttall: Cat. Pl. Upper Louisiana, no. 53. (1813) | Torrey & A. Gray: Fl. N. Amer. 1: 498. (1840) | ||||||||||||||||||||||||||||
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