Oenothera clelandii

Herbs biennial, densely to sometimes sparsely strigillose, or also sparsely glandular puberulent distally. Stems sometimes with lateral branches arising obliquely from rosette, 20–70(–100) cm. Leaves in a basal rosette and cauline, basal 5–16 × 0.5–1.5 cm, cauline 2–12 × 0.5–2 cm; blade narrowly oblanceolate, gradually narrowly elliptic to narrowly lanceolate distally, margins lobed to remotely dentate or subentire; bracts slightly longer than capsule they subtend. Inflorescences dense, without lateral branches, mature buds usually not overtopping spike apex. Flowers 2–several per spike opening per day near sunset; buds erect, with free tips erect, 0.5–2 mm; floral tube slightly curved upward to± straight, 15–40 mm; sepals 6–13 mm; petals yellow, broadly elliptic to rhombic-ovate, 5–16 mm; filaments 4–18 mm, anthers 2–3.5 mm, pollen ca. 50% fertile; style 20–40 mm, stigma surrounded by anthers at anthesis. Capsules narrowly lanceoloid, 10–20 ×2–3 mm. Seeds brown, sometimes flecked with dark red spots, ellipsoid, 1–1.9 × 0.4–0.8 mm. 2n = 14.

Phenology: Flowering Jun–Aug(–Sep).
Habitat: Fields, prairies, sandy soil.
Elevation: 150–300 m.

Ont., Ark., Ill., Ind., Iowa, Ky., Mich., Minn., Mo., N.J., N.Y., Va., Wis.

Discussion

Oenothera clelandii is a PTH species and forms a ring of 14 chromosomes in meiosis, and is self-compatible and autogamous (W. Dietrich and W. L. Wagner 1988). Some localities in the easternmost states may represent introductions, primarily occurring in disturbed areas along roads and railroad lines.

Selected References

None.

Lower Taxa