Oenothera spachiana
Fl. N. Amer. 1: 498. 1840.
Herbs annual, densely strigillose; from a sparsely branched taproot. Stems erect, usually unbranched or with few ascending branches, 10–30(–45) cm. Leaves 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 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 broadly clavate, 4-angled, 5–15 × 3–5 mm, stipe 2–5 mm; sessile. Seeds 1 × 0.5 mm. 2n = 14.
Phenology: Flowering Mar–May.
Habitat: Prairies, open roadsides, sandy places.
Elevation: 10–200 m.
Distribution
Ala., Ark., La., Miss., Okla., Tex.
Discussion
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.
Selected References
None.