Oenothera glaucifolia |
Oenothera cespitosa |
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false gaura |
fragrant evening-primrose, tuft evening-primrose |
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Habit | Herbs probably biennial, glabrous, becoming sparsely to densely glandular puberulent and short-villous distally, glaucous at least in proximal parts; from stout roots. | 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. | ||||||||||||||||||||||||||||
Stems | erect, branched or unbranched, 30–300 cm. |
(when present), usually ascending or decumbent, unbranched or branched from near base, 0–40 cm. |
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Leaves | in a basal rosette and cauline, basal 3–7 × 0.5–2 cm, sessile, blade oblong to oblong-lanceolate, base usually ± auriculate, margins entire; cauline 3–8(–10) × 0.4–1.8 cm, blade lanceolate to oblong-lanceolate, gradually smaller, becoming linear-subulate distally. |
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. |
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Inflorescences | long, wandlike, unbranched or branched. |
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Flowers | 4-merous, nearly actinomorphic, opening near sunrise; floral tube 6–17 mm; sepals 4–6 mm; petals white, fading off-white or tinged pink, slightly unequal, rhombic, 4–6 mm, abruptly clawed; filaments 5–8 mm, anthers 1.5–2 mm, pollen 85–100% fertile; style 6–10, stigma exserted beyond anthers at anthesis. |
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. |
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Capsules | ovoid, 4-angled, somewhat flattened, 3–4 × 1.5–2.3 mm, valves with raised midrib and conspicuous lateral veins; sessile. |
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. |
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Seeds | 1, pale yellow, oblanceoloid, 2.4–2.6 × 1–1.5 mm. |
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. |
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2n | = 14. |
= 14, 28. |
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Oenothera glaucifolia |
Oenothera cespitosa |
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Phenology | Flowering May–Oct(–Nov). | |||||||||||||||||||||||||||||
Habitat | Rocky prairie slopes and outcrops or bluffs, along streams, roadsides, usuallyon limestone. | |||||||||||||||||||||||||||||
Elevation | 200–1300 m. (700–4300 ft.) | |||||||||||||||||||||||||||||
Distribution |
AR; CO; KS; MO; NE; NM; OK; TX; WY
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w North America; nw Mexico
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Discussion | Oenothera glaucifolia is self-incompatible, the flowers diurnal, pollinated primarily by wasps (R. Clinebell, unpubl.), as well as bees, flies, butterflies, and occasionally beetles (summarized by W. L. Wagner et al. 2007). It was collected once in 1988 in Indiana at Miller Woods Visitor Center (Lake County), Dritz 596 (MOR); it seems likely that it was introduced, and has not been collected there since. Stenosiphon virgatus Spach is a superfluous name and pertains here. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
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.) |
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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. Gaura > subsect. Stenosiphon | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Pachylophus | ||||||||||||||||||||||||||||
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Synonyms | Gaura linifolia, Stenosiphon linifolius | Pachylophus cespitosus | ||||||||||||||||||||||||||||
Name authority | W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 212. (2007) | Nuttall: Cat. Pl. Upper Louisiana, no. 53. (1813) | ||||||||||||||||||||||||||||
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