Oenothera pilosella |
Oenothera arida |
|
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meadow evening-primrose |
trans-Pecos beeblossom |
|
Habit | Herbs perennial, usually densely to sparsely hirsute, rarely glabrous; from a thickened base, rhizomatous. | Herbs perennial, clumped, strigillose and glandular puberulent throughout, also sparsely villous; from stout roots. |
Stems | spreading or ascending, unbranched or few-branched distally, 20–80 cm. |
erect, usually branched several cm belowground or from near base, sometimes also branched distally, 20–60(–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 2–4 × 0.4–0.8 cm, petiole0–0.4 cm, blade narrowly oblanceolate to narrowly spatulate; cauline 0.5–5 × 0.1–0.8 cm, petiole 0–0.3 cm, blade narrowly lanceolate or very narrowly elliptic, margins subentire or sinuate-denticulate. |
Inflorescences | erect, flowers in axils of distalmost few nodes. |
|
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. |
4-merous, nearly actinomorphic, opening near sunset; floral tube 9–13 mm; sepals 7–9 mm; petals white, fading pink to pale red, slightly unequal, rhombic, 7–8 mm, short-clawed; filaments 3–4 mm, anthers 4–5 mm, pollen 85–100% fertile; style 18–22 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, fusiform, often slightly curved, weakly 4-angled, (9–)13–17 × 2–3 mm, valves with inconspicuous raised midrib; sessile. |
Seeds | 1 × 0.5 mm. |
(1–)3 or 4, yellowish or light brown, 2–3.5 × 1–2 mm. |
2n | = 56. |
= 14. |
Oenothera pilosella |
Oenothera arida |
|
Phenology | Flowering May–Jul(–Aug). | Flowering Apr–Aug. |
Habitat | Open fields, edge of woods, marshes and bottomland prairies, open disturbed sites, ditches, old fields, railroads, roadsides. | Sandy flats and washes. |
Elevation | 100–600 m. (300–2000 ft.) | 1300–1800 m. (4300–5900 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
|
TX; Mexico (Chihuahua) |
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 arida is known only from several areas in the foothills of the Davis Mountains in eastern Jeff Davis County, northeastern Presidio County, and northern Brewster County, and from areas near Gallego and Chihuahua in Chihuahua, Mexico. P. H. Raven and D. P. Gregory (1972[1973]) determined O. arida to be self-incompatible. (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. Gaura > subsect. Xerogaura |
Sibling taxa | ||
Synonyms | Kneiffia fruticosa var. pilosella, K. pilosella, K. pratensis, K. sumstinei, O. fruticosa var. hirsuta, O. fruticosa var. pilosella, O. pratensis | Gaura macrocarpa |
Name authority | Rafinesque: Ann. Nat. 1: 15. (1820) | W. L. Wagner & Hoch: Syst. Bot. Monogr. 83: 211. (2007) |
Web links |