Oenothera pilosella |
Oenothera grandis |
|
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meadow evening-primrose |
largeflower eveningprimrose, showy evening-primrose |
|
Habit | Herbs perennial, usually densely to sparsely hirsute, rarely glabrous; from a thickened base, rhizomatous. | Herbs annual, strigillose and sparsely villous, also glandular puberulent distally. |
Stems | spreading or ascending, unbranched or few-branched distally, 20–80 cm. |
erect to ascending, often with ascending lateral branches, 15–60(–100) 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 basal rosette and cauline, basal 5–13 × 1–3 cm, cauline 3–10 × 1.5–3.5 cm; blade green, narrowly oblanceolate to narrowly elliptic, margins lobed or dentate, lobes often dentate; bracts spreading, flat. |
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–few opening per day near sunset; buds erect, with free tips terminal, erect or hornlike, 1.5–5 mm; floral tube 25–45 mm; sepals 15–30 mm; petals yellow, very broadly obovate or shallowly obcordate, 25–40 mm; filaments 12–22 mm, anthers 4–11 mm, pollen 85–100% fertile; style 40–75 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. |
cylindrical, sometimes slightly enlarged toward apex, 25–50 ×2–3 mm. |
Seeds | 1 × 0.5 mm. |
broadly ellipsoid to subglobose, 0.8–1.5 × 0.5–0.9 mm. |
2n | = 56. |
= 14. |
Oenothera pilosella |
Oenothera grandis |
|
Phenology | Flowering May–Jul(–Aug). | Flowering Mar–Sep. |
Habitat | Open fields, edge of woods, marshes and bottomland prairies, open disturbed sites, ditches, old fields, railroads, roadsides. | Open, sandy sites. |
Elevation | 100–600 m. (300–2000 ft.) | 0–1500(–2200) m. (0–4900(–7200) 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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AL; AR; CO; CT; FL; IL; IN; KS; LA; MD; MI; MO; NC; NE; NJ; NM; TX; Mexico (Tamaulipas)
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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 grandis is probably native to eastern New Mexico and Colorado, Arkansas, Kansas, Louisiana, Missouri, Nebraska, Oklahoma, and Texas, and northeastern Tamaulipas, Mexico. Scattered collections made in other states probably represent introductions (W. Dietrich and W. L. Wagner 1988). Oenothera grandis is self-incompatible (W. Dietrich and W. L. Wagner 1988). Oenothera laciniata Hill var. occidentalis Small and O. laciniata var. grandis Britton are illegitimate superfluous names based on O. sinuata Linnaeus var. grandiflora S. Watson and pertain here. (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. Oenothera > subsect. Raimannia |
Sibling taxa | ||
Synonyms | Kneiffia fruticosa var. pilosella, K. pilosella, K. pratensis, K. sumstinei, O. fruticosa var. hirsuta, O. fruticosa var. pilosella, O. pratensis | O. laciniata var. grandiflora, O. sinuata var. grandiflora, Raimannia grandis |
Name authority | Rafinesque: Ann. Nat. 1: 15. (1820) | Smyth: Trans. Kansas Acad. Sci. 16: 160. (1899) |
Web links |