Oenothera pilosella |
Oenothera toumeyi |
|
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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 or sometimes annual, glabrate to strigillose throughout; from a stout taproot. |
Stems | spreading or ascending, unbranched or few-branched distally, 20–80 cm. |
1–several, ascending to erect, unbranched to densely branched, 15–70 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. |
1–3.5 × 0.1–0.7 cm, fascicles of small leaves 0.2–2.5 cm present in non-flowering axils; petiole 0 cm; blade narrowly lanceolate, base acute-attenuate, margins entire or obscurely and sparsely serrulate, not undulate, apex acute. |
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 at sunset; buds with free tips 2–9(–12) mm; floral tube (15–)30–60(–70) mm, funnelform in distal 1/2 or less; sepals 10–25 mm; petals yellow, fading pale pink or pale purple, 10–20 mm; filaments 4–12 mm, anthers 6–10 mm, pollen 85–100% fertile; style 35–70(–80) 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. |
10–50 × 1.5–4 mm, somewhat papery, promptly dehiscent in distal 1/2. |
Seeds | 1 × 0.5 mm. |
obovoid, 2–3 mm. |
2n | = 56. |
= 14. |
Oenothera pilosella |
Oenothera toumeyi |
|
Phenology | Flowering May–Jul(–Aug). | Flowering (May–)Jul–Oct. |
Habitat | Open fields, edge of woods, marshes and bottomland prairies, open disturbed sites, ditches, old fields, railroads, roadsides. | Local and uncommon on shaded, rocky slopes or disturbed areas, pine-oak forests. |
Elevation | 100–600 m. (300–2000 ft.) | 1500–2600 m. (4900–8500 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; NM; Mexico (Chihuahua, Sonora) |
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 toumeyi occurs locally from the Chiricahua, Huachuca, and Santa Rita mountains in Cochise and Santa Cruz counties, Arizona, and the Mogollon Mountains in southern Catron County, New Mexico, south through northeastern Sonora in the Sierra Madre Occidental to west-central Chihuahua. H. F. Towner (1977) found that O. toumeyi 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 | Galpinsia toumeyi, Calylophus hartwegii subsp. toumeyi, C. hartwegii var. toumeyi, C. toumeyi, O. hartwegii var. toumeyi |
Name authority | Rafinesque: Ann. Nat. 1: 15. (1820) | (Small) Tidestrom: Proc. Biol. Soc. Wash. 48: 41. (1935) |
Web links |