Oenothera linifolia |
Oenothera albicaulis |
|
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threadleaf evening-primrose, threadleaf sundrop |
white-stem evening-primrose, whitest evening primrose, whitish evening primrose |
|
Habit | Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. | Herbs winter-annual, densely strigillose, also sparsely villous; from a taproot. |
Stems | unbranched or with many ascending branches arising near base, erect, 10–50 cm. |
ascending to decumbent, 1–several from base, sometimes unbranched, erect or ascending, 5–30 cm. |
Leaves | in a basal rosette and cauline, basal 1–2(–4) × 0.2–0.6 cm, petiole 0.2–1(–1.5) cm, blade ovate to obovate or narrowly elliptic; cauline 1–4 × less than 0.1 cm, sessile, blade linear or filiform. |
in a basal rosette and cauline, 1.5–10 × 0.3–2.5 cm; blade oblanceolate to oblong, margins subentire or coarsely dentate or pinnatifid. |
Flowers | usually 1–3 opening per day near sunrise; buds without free tips; sepals 1.5–2 mm; petals bright yellow, fading pink, obcordate to obovate, 3–5(–7) mm; filaments 1–2 mm, anthers 0.5–1 mm; style 1–2 mm, stigma surrounded by anthers at anthesis. |
1–3 opening per day near sunset; buds nodding, weakly quadrangular, without free tips; floral tube 15–30 mm, mouth glabrous; sepals 15–30 mm; petals white, fading pink, usually obcordate, sometimes obovate, (15–)20–35(–40) mm; filaments 11–17 mm, anthers 6–10 mm; style 25–50 mm, stigma exserted beyond anthers at anthesis. |
Capsules | ellipsoid-rhombic to subglobose, 4-angled, 4–6(–10) × 1.5–3 mm, stipe 0–4 mm, valve midrib raised at distal end, indehiscent or tardily dehiscent distally; sessile. |
ascending to erect, usually straight, sometimes curved, cylindrical, weakly 4-angled, 20–40 × 3–4 mm, dehiscent 1/2 their length; sessile. |
Seeds | clustered in each locule, ovoid, surface minutely papillose, 1 × 0.5 mm. |
in 2 rows per locule, ellipsoid to subglobose, 0.8–1.5 × 0.5–0.9 mm, surface regularly pitted, pits in longitudinal lines. |
2n | = 14. |
= 14. |
Oenothera linifolia |
Oenothera albicaulis |
|
Phenology | Flowering Apr–Jun(–Aug). | Flowering (Feb–)Mar–Jun(–Dec). |
Habitat | Prairies, open woodlands, open rocky and sandy sites, roadsides. | Dry, usually sandy flats and slopes. |
Elevation | 0–400 m. (0–1300 ft.) | 1000–2300 m. (3300–7500 ft.) |
Distribution |
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX
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AZ; CO; ID; KS; MT; ND; NE; NM; OK; SD; TX; UT; WY; Mexico (Chihuahua, Sonora)
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Discussion | Kneiffia linearifolia Spach (1835) is an illegitimate name based on Oenothera linifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
Oenothera albicaulis is self-incompatible (W. L. Wagner et al. 2007; K. E. Theiss et al. 2010). Oenothera albicaulis has been reported from southern Nevada, but documentation is needed of its occurrence there. Anogra pinnatifida Spach, Baumannia pinnatifida Spach, Oenothera pinnatifida Nuttall, O. purshiana Steudel, and O. purshii G. Don are illegitimate names that 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. Peniophyllum | Onagraceae > subfam. Onagroideae > tribe Onagreae > Oenothera > sect. Kleinia |
Sibling taxa | ||
Synonyms | Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium | Anogra albicaulis, A. bradburiana, A. buffumii, A. confusa, A. ctenophylla, A. perplexa, O. albicaulis var. xanthosperma, O. ctenophylla, O. sinuata var. bicolor |
Name authority | Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) | Pursh: Fl. Amer. Sept. 2: 733. (1813) |
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