Oenothera acutissima |
Oenothera curtissii |
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flaming Gorge evening primrose |
Curtiss' evening primrose |
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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 biennial or short-lived perennial, densely to sparsely strigillose, sometimes also sparsely glandular puberulent distally. |
Stems | (when present) ascending, (1–)several–10, densely leafy, 1–2 cm. |
sometimes with lateral branches arisingobliquely from rosette, 30–80 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 7–17 × 0.5–1.5 cm, cauline 2–8 × 0.5–1.5 cm; blade narrowly oblanceolate, gradually narrowly elliptic to narrowly oblong distally, margins lobed to remotely dentate or subentire; bracts slightly longer than capsule they subtend. |
Inflorescences | open, lax, without lateral branches, mature buds usually not overtopping spike apex. |
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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. |
1 or 2 per spike opening per day near sunset; buds erect, with free tips erect to spreading, 0.3–0.8 mm; floral tube slightly curved upward to straight, 23–37 mm; sepals 7–13 mm; petals yellow, broadly elliptic to rhombic-ovate, 8–17 mm; filaments 6–10 mm, anthers 1.5–4 mm, pollen ca. 50% fertile; style 30–45 mm, stigma surrounded by anthers at anthesis. |
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 lanceoloid, 10–25 ×2–3 mm. |
Seeds | asymmetrically cuneiform, 2–2.5 mm. |
brown, sometimes flecked with darkred spots, ellipsoid, 1–1.3 × 0.5–0.7 mm. |
2n | = 14. |
= 14. |
Oenothera acutissima |
Oenothera curtissii |
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Phenology | Flowering May–Jun. | Flowering Jun–Sep. |
Habitat | Restricted to sandy and gravelly, reddish, soil in seasonally wet sites, meadows, depressions, along arroyos, among rocks, in mixed conifer forests, sagebrush scrub. | Dry places, pine-oak woods, fields, roadsides, sandy soil. |
Elevation | 1800–2400(–2600) m. (5900–7900(–8500) ft.) | 0–60 m. (0–200 ft.) |
Distribution |
CO; UT |
AL; FL; GA; SC |
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 curtissii 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). It is known only from northern Florida, adjacent southern Georgia and southeastern Alabama, and one disjunct locality in South Carolina (Allendale County). (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 | O. heterophylla var. curtissii |
Name authority | W. L. Wagner: Syst. Bot. 6: 153, fig. 1. (1981) | Small: Fl. S.E. U.S. ed. 2, 1353. (1913) |
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