Oenothera acutissima |
Oenothera triangulata |
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flaming Gorge evening primrose |
prairie beeblossom |
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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, villous proximally, sparsely villous along veins and on margins, usually glabrate, sometimes strigillose distally; from taproot. |
Stems | (when present) ascending, (1–)several–10, densely leafy, 1–2 cm. |
ascending, usually well-branched from base and distally, rarely unbranched, 15–60 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, 1.5–8 × 0.2–0.6(–1.5) cm, blade very narrowly elliptic to oblanceolate or oblong-elliptic, margins entire or weakly sinuate-dentate. |
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. |
3(or 4)-merous, zygomorphic, opening at sunset; floral tube 4–5.5 mm; sepals 4.5–6 mm; petals white, fading pink, elliptic-obovate, 3.5–5 mm; filaments 2–3.5 mm, anthers 1.5–3 mm, pollen 35–65% fertile; style 9–10 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. |
narrowly obovoid, 3(or 4)-winged, furrowed between wings, 7–9 × 3–5 mm, narrowed at base; sessile. |
Seeds | asymmetrically cuneiform, 2–2.5 mm. |
(1 or)2–5, yellowishto light brown, 1.5–3.5 × 1–1.5 mm. |
2n | = 14. |
= 14. |
Oenothera acutissima |
Oenothera triangulata |
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Phenology | Flowering May–Jun. | Flowering Apr–Jul. |
Habitat | Restricted to sandy and gravelly, reddish, soil in seasonally wet sites, meadows, depressions, along arroyos, among rocks, in mixed conifer forests, sagebrush scrub. | Open, sandy sites. |
Elevation | 1800–2400(–2600) m. (5900–7900(–8500) ft.) | 200–600 m. (700–2000 ft.) |
Distribution |
CO; UT |
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.) |
Oenothera triangulata is a PTH species and forms a ring of 14 chromosomes in meiosis. The species is self-compatible and autogamous (P. H. Raven and D. P. Gregory 1972[1973]). It may have been derived from hybridization between O. patriciae and O. suffulta. The species has a relatively narrow distribution across south-central Oklahoma and north-central Texas (Oklahoma in Cleveland, Comanche, Cotton, Grady, Oklahoma, Rogers, Stephens, and Tulsa counties; Texas in Archer, Baylor, Callahan, Clay, Coleman, Crosby, Eastland, Erath, Jones, Montague, Taylor, Throckmorton, Tom Greene, Wichita, Wilbarger, and Young counties). (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 | Gaura triangulata, G. hexandra var. triangulata, G. tripetala var. triangulata |
Name authority | W. L. Wagner: Syst. Bot. 6: 153, fig. 1. (1981) | (Buckley) W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 214. (2007) |
Web links |