Herbs annual or short-lived perennial, sparsely to densely strigillose, inflorescence some­times also sparsely glandular puberulent, villous, or sparsely hirsute with spreading, pustulate-based hairs, or some­times glabrate. Stems unbranched or branched mainly in distal part, 25–70 cm. Leaves in a basal rosette and cauline, basal 7–15 × 1–2.5 cm, cauline 3–13 ×0.4–2.3 cm; blade narrowly oblanceolate to oblan­ceolate, gradually narrowly lanceolate to lanceolate or elliptic distally, margins deeply lobed to remotely dentate or subentire; bracts longer than capsule they subtend, 1–3 cm. Inflorescences dense, often with several lateral branches, mature buds usually overtopping spike apex. Flowers 2–several per spike opening per day near sunset; buds erect, with free tips erect or spreading, 1–6 mm; floral tube nearly straight, 25–47 mm; sepals 15–30 mm; petals yellow, broadly elliptic to nearly rhombic, 18–35 mm; filaments 15–30 mm, anthers 3–8 mm, pollen 85–100% fertile; style 45–75 mm, stigma usually exserted beyond anthers at anthesis. Capsules lanceoloid, 13–25 × 2.5–4 mm. Seeds brown, often flecked with darker spots, ellipsoid to broadly ellipsoid, 1.1–1.8 × 0.4–0.8 mm.

Distribution

s United States.

Discussion

Subspecies 2 (2 in the flora).

Selected References

None.

Lower Taxa

Oenothera heterophylla subsp. heterophylla, Oenothera heterophylla subsp. orientalis

Key

1	Herbs densely to sparsely strigillose, also at least parts of inflorescence sparsely hirsute with spreading, pustulate-based hairs, and often glandular puberulent and villous; flower buds with free tips spreading, 2–6 mm.	Oenothera heterophylla subsp. heterophylla
1	Herbs densely to sparsely strigillose, also at least part of inflorescence glabrate or glandular puberulent; flower buds with free tips erect, 1–3 mm.	Oenothera heterophylla subsp. orientalis