Oenothera kunthiana

Herbs annual, strigillose and also hirsute; from a slender taproot. Stems 5–40 cm. Leaves 1–6 × 0.3–3 cm; petiole 0.1–1.1 cm; blade usually lanceolate to oblanceolate, sometimes elliptic, margins weakly serrate to sinuate-pinnatifid. Flowers 1–3 opening per day near sunset; buds with free tips 0–0.5 mm; floral tube 5–31 mm; sepals 10–27 mm; petals white, fading pink, 8–25 mm; filaments 6–12 mm, anthers 3–5 mm, pollen 35–65% fertile; style 12–30 mm, stigma surrounded by anthers at anthesis. Capsules broadly clavate or obovoid, 7–31 ×3–5 mm, winged, wings 0.5–1.5 mm, valve surface with prominent midrib, proximal stipe 3–17 mm; sessile. Seeds narrowly obovoid, 0.9–1.2 × 0.4–0.5 mm. 2n = 14.

Phenology: Flowering Feb–May.
Habitat: Alluvial flats, open areas, sandy soil, weedy sites.
Elevation: 10–1300[–2000] m.

Tex., Mexico, Central America, n South America, introduced widely in temperate Europe, Asia, Pacific Islands (Hawaii), Australia.

Discussion

Oenothera kunthiana is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous, common and widespread from sea level to middle elevations in the mountains from southern Texas south throughout Mexico except for Baja California and the tropical lowlands southward to Guatemala, Nicaragua, and Costa Rica; it was once collected in Minas Gerais, Brazil. Oenothera kunthiana was recently found to be naturalized in the Hawaiian Islands.

Oenothera pinnatifida Kunth is a later homonym of O. pinnatifida Nuttall and another later homonym is O. micrantha Walpers, not Hornemann ex Sprengel (1825); they both pertain here.

Selected References

None.

Lower Taxa