Oenothera linifolia |
Oenothera spachiana |
|
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threadleaf evening-primrose, threadleaf sundrop |
spach's evening primrose |
|
Habit | Herbs annual, caulescent, strigillose or glabrous, also often glandular puberulent, especially distally; from a sparsely branched taproot. | Herbs annual, densely strigillose; from a sparsely branched taproot. |
Stems | unbranched or with many ascending branches arising near base, erect, 10–50 cm. |
erect, usually unbranched or with few ascending branches, 10–30(–45) 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, basal 2–5 × 0.5–1.5 cm, petiole 0.5–2 cm, blade oblanceolate to elliptic, margins subentire; cauline 3–6 × 0.2–0.6 cm, petiole 0.2–0.6(–1.5) cm, blade narrowly lanceolate to linear, margins subentire. |
Inflorescences | erect, flowers in leaf axils in distal 1/2 of plant. |
|
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. |
opening near sunrise; buds with free tips to 1 mm, erect to spreading; floral tube 4–10 mm; sepals 4–8 mm; petals pale yellow, fading pale pink, 5–14 mm; filaments 3–7 mm, anthers 2–4 mm, pollen 85–100% fertile; style 3–7 mm, stigma surrounded by anthers. |
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. |
broadly clavate, 4-angled, 5–15 × 3–5 mm, stipe 2–5 mm; sessile. |
Seeds | clustered in each locule, ovoid, surface minutely papillose, 1 × 0.5 mm. |
1 × 0.5 mm. |
2n | = 14. |
= 14. |
Oenothera linifolia |
Oenothera spachiana |
|
Phenology | Flowering Apr–Jun(–Aug). | Flowering Mar–May. |
Habitat | Prairies, open woodlands, open rocky and sandy sites, roadsides. | Prairies, open roadsides, sandy places. |
Elevation | 0–400 m. (0–1300 ft.) | 10–200 m. (0–700 ft.) |
Distribution |
AL; AR; FL; GA; IL; KS; KY; LA; MO; MS; NC; OK; SC; TN; TX
|
AL; AR; LA; MS; OK; TX |
Discussion | Kneiffia linearifolia Spach (1835) is an illegitimate name based on Oenothera linifolia. (Discussion copyrighted by Flora of North America; reprinted with permission.) |
G. B. Straley (1977) determined Oenothera spachiana to be self-compatible and autogamous. Collections outside the native range of O. spachiana have been made as a ballast weed in Camden County, New Jersey. Oenothera drummondii (Spach) Walpers (1843), not Hooker (1834) is a later homonym and pertains 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. Kneiffia |
Sibling taxa | ||
Synonyms | Kneiffia linifolia, O. linifolia var. glandulosa, Peniophyllum linifolium | Blennoderma drummondii, Kneiffia spachiana, O. uncinata |
Name authority | Nuttall: J. Acad. Nat. Sci. Philadelphia 2: 120. (1821) | Torrey & A. Gray: Fl. N. Amer. 1: 498. (1840) |
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