Oenothera pilosella |
Oenothera argillicola |
|
---|---|---|
meadow evening-primrose |
shale barren evening primrose |
|
Habit | Herbs perennial, usually densely to sparsely hirsute, rarely glabrous; from a thickened base, rhizomatous. | Herbs biennial or short-lived perennial, strigillose and sparsely to moderately villous, hairs sometimes pustulate, pustules with green or red bases, inflorescence glabrous or sparsely glandular puberulent, sometimes also sparsely villous. |
Stems | spreading or ascending, unbranched or few-branched distally, 20–80 cm. |
erect to ascending, green or red, unbranched or with branches obliquely arising from rosette or in distal 1/2 of main stem. |
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 7–25 × 0.7–2 cm, cauline 6–13 × 0.4–1 cm; blade dark green, somewhat glossy, very narrowly oblanceolate to narrowly oblanceolate, linear-elliptic, lanceolate, or nearly linear, margins flat, entire or remotely and bluntly dentate, sometimes with larger teeth near base; bracts persistent. |
Inflorescences | erect, flowers in axils of distalmost few nodes. |
curved with ascending tip, unbranched. |
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, 4–8 mm diam., with free tips subterminal, divergent and hornlike, 3–9 mm; floral tube 32–52 mm; sepals yellowish green to yellow, sometimes flushed with red, especially at apex, 27–38 mm; petals yellow to pale yellow, fading pale yellow to pale yellowish orange, very broadly obcordate or obovate, 25–42 mm; filaments 20–27 mm, anthers 9–13 mm, pollen 90–100% fertile; style 60–85 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. |
spreading at nearly a right angle to stem, curved upward, sometimes secund, dull green or rusty brown when dry, narrowly lanceoloid to lanceoloid, 20–40 × 4–6 mm, free tips of valves 1–2 mm. |
Seeds | 1 × 0.5 mm. |
1.3–1.9 × 0.7–1.1 mm. |
2n | = 56. |
= 14. |
Oenothera pilosella |
Oenothera argillicola |
|
Phenology | Flowering May–Jul(–Aug). | Flowering (Jun–)Jul–Oct. |
Habitat | Open fields, edge of woods, marshes and bottomland prairies, open disturbed sites, ditches, old fields, railroads, roadsides. | Open sites on Devonian Brallier shale slopes, barrens, outcrops or adjacent roadsides in mid-Appalachian Allegheny Mountains. |
Elevation | 100–600 m. (300–2000 ft.) | 150–700 m. (500–2300 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
|
MD; PA; VA; WV |
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 argillicola is one of eight angiosperm species restricted to the Devonian Brallier shale barrens, but among them only O. argillicola and Trifolium virginicum occur throughout the shale barren region. Oenothera argillicola has plastome V and a CC genome composition. (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 | O. argillicola var. pubescens |
Name authority | Rafinesque: Ann. Nat. 1: 15. (1820) | Mackenzie: Torreya 4: 56. (1904) |
Web links |