Oenothera pilosella |
Oenothera lavandulifolia |
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meadow evening-primrose |
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Habit | Herbs perennial, usually densely to sparsely hirsute, rarely glabrous; from a thickened base, rhizomatous. | Herbs perennial, densely strigillose throughout, sometimes glandular puberulent distally; from a stout taproot. |
Stems | spreading or ascending, unbranched or few-branched distally, 20–80 cm. |
several to many, decumbent to ascending, branched, 4–20(–30) cm. |
Leaves | in a basal rosette and cauline, basal 4–8 × 2–5 cm, petiole (0.5–)1–3(–4) cm, blade oblanceolate to ovate, margins entire; cauline 3–10(–13) × 1–2(–4) cm, petiole 0–0.5(–2) cm, blade lanceolate to ovate, abruptly narrowed to base, margins subentire or coarsely dentate. |
0.6–5 × 0.08–0.6 cm, fascicles of small leaves 0.2–1 cm often present in non-flowering axils; petiole 0 cm; blade narrowly lanceolate or narrowly oblanceolate, base attenuate to truncate, sometimes clasping, margins entire or subentire, sometimes revolute, sometimes weakly undulate, apex acute to obtuse. |
Inflorescences | erect, flowers in axils of distalmost few nodes. |
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Flowers | opening near sunrise; buds with free tips 1–3 mm, spreading; floral tube 10–25 mm; sepals 10–20 mm; petals bright yellow, fading pale pink or pale yellow, 15–30 mm; filaments 7–15 mm, anthers 4–8 mm, pollen 85–100% fertile; style 10–20 mm, stigma exserted beyond anthers at anthesis. |
usually 1 per stem opening per day near sunset; buds with free tips 0.3–3 mm; floral tube 25–60 mm, funnelform in distal 1/2 or less; sepals 8–20 mm; petals yellow, fading pale pink or pale purple, 12–28 mm; filaments 6–12 mm, anthers 5–11 mm, pollen 85–100% fertile; style 30–75 mm, stigma yellow, quadrangular, usually exserted beyond anthers. |
Capsules | usually oblong-clavate to oblong-ellipsoid or ellipsoid, 4-angled or weakly 4-winged, (5–)10–15(–28) × 2–4(–5) mm, stipe (1–)3–5(–9) mm; sessile. |
6–25 × 1–3 mm, hard, promptly dehiscent throughout their length. |
Seeds | 1 × 0.5 mm. |
obovoid, 1.5–2.5 mm. |
2n | = 56. |
= 14. |
Oenothera pilosella |
Oenothera lavandulifolia |
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Phenology | Flowering May–Jul(–Aug). | Flowering Apr–Aug. |
Habitat | Open fields, edge of woods, marshes and bottomland prairies, open disturbed sites, ditches, old fields, railroads, roadsides. | Local and sparse, on sandy and rocky, calcareous soil, high plains, mountains, often with Artemisia tridentata, Cercocarpus, Juniperus, Pinus edulis, or P. monophylla, sometimes in lower zones with Larrea, or in higher zones with P. ponderosa. |
Elevation | 100–600 m. (300–2000 ft.) | 600–2800 m. (2000–9200 ft.) |
Distribution |
AL; AR; CT; IA; IL; IN; KY; LA; MA; ME; MI; MO; MS; NH; NY; OH; OK; PA; RI; VA; VT; WI; WV; ON
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AZ; CO; KS; NE; NM; OK; SD; TX; WY; Mexico (Nuevo León) |
Discussion | Oenothera pilosella is widespread in cultivation in gardens and frequently escapes and becomes naturalized; the northern and eastern natural limits of O. pilosella are not clear. According to G. B. Straley (1977) the natural limits are from Wayne County, West Virginia, along the Ohio River and Erie County, New York, for the eastern limits, and Tuscola County, Michigan, and Manitowoc County, Wisconsin, for the northern limits. K. N. Krakos (2014), based on new field studies and phylogenetic data, found that O. pilosella does not form a monophyletic group with plants previously treated by Straley as O. pilosella subsp. sessilis in molecular analyses, and thus is here reinstated as the distinct species O. sessilis. Straley determined that O. pilosella is self-incompatible and an octoploid, one of the few in the genus. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera lavandulifolia is known from southern Fall River County, South Dakota, southeastern Wyoming, and far western Nebraska, through western Kansas, Colorado, eastern and southern Utah, northwestern Oklahoma, and the Texas Panhandle to trans-Pecos Texas, central New Mexico, northern and central Arizona, and eastern Nevada. It also occurs in Nuevo León, Mexico, and may be more widespread in northern Mexico. H. F. Towner (1977) found that O. lavandulifolia is self-incompatible and vespertine. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Source | FNA vol. 10. | FNA vol. 10. |
Parent taxa | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Kneiffia | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Calylophus > subsect. Salpingia |
Sibling taxa | ||
Synonyms | Kneiffia fruticosa var. pilosella, K. pilosella, K. pratensis, K. sumstinei, O. fruticosa var. hirsuta, O. fruticosa var. pilosella, O. pratensis | Calylophus hartwegii subsp. lavandulifolius, C. hartwegii var. lavandulifolius, C. lavandulifolius, Galpinsia lavandulifolia, G. lavandulifolia var. glandulosa, O. hartwegii var. lavandulifolia, O. lavandulifolia var. glandulosa |
Name authority | Rafinesque: Ann. Nat. 1: 15. (1820) | Torrey & A. Gray: Fl. N. Amer. 1: 501. (1840) — (as lavandulaefolia) |
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