Oenothera pilosella |
Oenothera jamesii |
|
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meadow evening-primrose |
trumpet evening primrose |
|
Habit | Herbs perennial, usually densely to sparsely hirsute, rarely glabrous; from a thickened base, rhizomatous. | Herbs biennial or winter-annual, usually predominately and densely strigillose, sometimes also villous with scattered, appressed hairs, rarely with a few pustulate hairs, inflorescence sometimes also glandular puberulent. |
Stems | spreading or ascending, unbranched or few-branched distally, 20–80 cm. |
erect, usually green, rarely flushed with red, unbranched or with branches arising obliquely from rosette and secondary branches arising from main stem, 60–180 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 10–30 × 2.5–5 cm, cauline 4–20 × 1–5 cm; blade dull green, flat, narrowly oblanceolate, oblanceolate to narrowly elliptic, or narrowly lanceolate, margins bluntly dentate or subentire, teeth widely spaced; bracts persistent. |
Inflorescences | erect, flowers in axils of distalmost few nodes. |
erect, usually unbranched, rarely with few lateral branches. |
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. |
opening near sunset; buds erect, 7–12 mm diam., with free tips terminal, erect, 0.5–3 mm; floral tube persistent on ovary after anthesis, (60–)80–120(–160) mm; sepals yellowish green, red-striped to red throughout, 30–55 mm; petals yellow, fading orange or pale yellow, very broadly obcordate, 40–50 mm; filaments 23–30 mm, anthers 12–22 mm, pollen 90–100% fertile; style 90–170(–200) 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. |
erect or slightly spreading, dull green or gray-green when dry, narrowly lanceoloid, 20–50 × 6–12 mm, free tips of valves 2.5–5 mm. |
Seeds | 1 × 0.5 mm. |
1–1.2 × 0.7–1.3 mm. |
2n | = 56. |
= 14. |
Oenothera pilosella |
Oenothera jamesii |
|
Phenology | Flowering May–Jul(–Aug). | Flowering Jul–Sep(–Oct). |
Habitat | Open fields, edge of woods, marshes and bottomland prairies, open disturbed sites, ditches, old fields, railroads, roadsides. | Sandy stream banks, ditches, moist areas, cultivated areas, disturbed roadsides. |
Elevation | 100–600 m. (300–2000 ft.) | (30–)300–1800 m. ((100–)1000–5900 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
|
KS; OK; TX; Mexico (Coahuila, Nuevo León, Puebla) [Introduced in e Asia (Japan), s Africa, Atlantic Islands (Canary Islands)] |
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 jamesii has plastome I and a AA genome composition; it is known in the flora area from southern Kansas (Clark County), central Oklahoma, and Texas. (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. Oenothera |
Sibling taxa | ||
Synonyms | Kneiffia fruticosa var. pilosella, K. pilosella, K. pratensis, K. sumstinei, O. fruticosa var. hirsuta, O. fruticosa var. pilosella, O. pratensis | Onagra jamesii, O. communis var. jamesii |
Name authority | Rafinesque: Ann. Nat. 1: 15. (1820) | Torrey & A. Gray: Fl. N. Amer. 1: 493. (1840) |
Web links |