Oenothera acutissima |
Oenothera spachiana |
|
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flaming Gorge evening primrose |
spach's evening primrose |
|
Habit | Herbs perennial, subacaulescent or very short-caulescent, strigillose mostly along leaf margins and flower parts, also sparsely glandular puberulent, sometimes also sparsely hirsute distally; from a stout taproot, usually with several long, lateral roots often producing adventitious shoots. | Herbs annual, densely strigillose; from a sparsely branched taproot. |
Stems | (when present) ascending, (1–)several–10, densely leafy, 1–2 cm. |
erect, usually unbranched or with few ascending branches, 10–30(–45) cm. |
Leaves | primarily in a basal rosette, 7–14(–18) × (0.3–)0.5–1(–1.5) cm, moderately thick and stiff; petiole (1.2–)3–5 cm; blade linear to very narrowly elliptic, margins irregularly and coarsely dentate or pinnately lobed, apex long-attenuate. |
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. |
Inflorescences | erect, flowers in leaf axils in distal 1/2 of plant. |
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Flowers | 1–3 opening per day near sunset; buds with unequal free tips 1–3 mm; floral tube (53–)60–100 mm; sepals 26–50 mm; petals bright yellow, fading deep reddish orange, drying purplish brown, 28–50 mm; filaments 21–35 mm, anthers 9–11 mm; style 75–143 mm, stigma exserted beyond anthers. |
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. |
Capsules | leathery in age, oblong-oblanceoloid, narrowly winged, wings oblong, 1–2(–4) mm wide, broadest near apex, 14–18(–22) × 7–8 mm (excluding wings), apex abruptly constricted, dehiscent 1/4–1/3 their length, valve surface with inconspicuous veins; sessile. |
broadly clavate, 4-angled, 5–15 × 3–5 mm, stipe 2–5 mm; sessile. |
Seeds | asymmetrically cuneiform, 2–2.5 mm. |
1 × 0.5 mm. |
2n | = 14. |
= 14. |
Oenothera acutissima |
Oenothera spachiana |
|
Phenology | Flowering May–Jun. | Flowering Mar–May. |
Habitat | Restricted to sandy and gravelly, reddish, soil in seasonally wet sites, meadows, depressions, along arroyos, among rocks, in mixed conifer forests, sagebrush scrub. | Prairies, open roadsides, sandy places. |
Elevation | 1800–2400(–2600) m. (5900–7900(–8500) ft.) | 10–200 m. (0–700 ft.) |
Distribution |
CO; UT |
AL; AR; LA; MS; OK; TX |
Discussion | Oenothera acutissima is known only from the vicinity of Manila, eastern Uinta Mountains, Daggett and Duchesne counties, Utah, east to areas in and near the foothills of the Douglas and Blue mountains, in Uinta County, Utah, and Moffat County, Colorado. (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.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | ||
Sibling taxa | ||
Synonyms | O. flava var. acutissima | Blennoderma drummondii, Kneiffia spachiana, O. uncinata |
Name authority | W. L. Wagner: Syst. Bot. 6: 153, fig. 1. (1981) | Torrey & A. Gray: Fl. N. Amer. 1: 498. (1840) |
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