Oenothera pilosella |
Oenothera coronopifolia |
|
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meadow evening-primrose |
crownleaf evening primrose |
|
Habit | Herbs perennial, usually densely to sparsely hirsute, rarely glabrous; from a thickened base, rhizomatous. | Herbs perennial, strigillose, usually also hirsute; from a taproot, lateral roots producing adventitious shoots. |
Stems | spreading or ascending, unbranched or few-branched distally, 20–80 cm. |
ascending to erect, 1–several from base, these unbranched to well-branched, 10–60 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. |
in a weakly developed basal rosette and cauline, 2–7 × 0.2–1.5 cm, axillary fascicles of reduced leaves often present; blade oblanceolate to oblong, margins usually pinnatifid, sometimes proximal ones coarsely few-toothed. |
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. |
1–3 opening per day near sunset; buds nodding, weakly quadrangular, without free tips; floral tube 10–25 mm, mouth conspicuously pubescent, closed with straight, white hairs, 1–2 mm; sepals 10–20 mm; petals white, fading pink, ovate or shallowly obcordate, 10–15(–20) mm; filaments 10–15 mm, anthers 4–7 mm; style 17–42 mm, stigma exserted beyond anthers at anthesis. |
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. |
ascending to erect, straight, fusiform, weakly 4-angled, 10–20 × 3–5 mm, dehiscent 1/2 their length; sessile. |
Seeds | 1 × 0.5 mm. |
in 2 rows per locule, ellipsoid to subglobose, 1.5–2 × 1.2–1.5 mm, surface regularly pitted, pits in longitudinal lines. |
2n | = 56. |
= 14, 28. |
Oenothera pilosella |
Oenothera coronopifolia |
|
Phenology | Flowering May–Jul(–Aug). | Flowering (Mar–)Jun–Aug(–Sep). |
Habitat | Open fields, edge of woods, marshes and bottomland prairies, open disturbed sites, ditches, old fields, railroads, roadsides. | Dry, open sites, grassy meadows, slopes, along drainages, foothills and mountains. |
Elevation | 100–600 m. (300–2000 ft.) | 1500–3000 m. (4900–9800 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; ID; NE; NM; SD; UT; WY
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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 coronopifolia apparently has both self-incompatible and self-compatible populations (P. H. Raven 1979; W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). (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. Kleinia |
Sibling taxa | ||
Synonyms | Kneiffia fruticosa var. pilosella, K. pilosella, K. pratensis, K. sumstinei, O. fruticosa var. hirsuta, O. fruticosa var. pilosella, O. pratensis | Anogra coronopifolia |
Name authority | Rafinesque: Ann. Nat. 1: 15. (1820) | Torrey & A. Gray: Fl. N. Amer. 1: 495. (1840) |
Web links |