Oenothera gayleana

Herbs perennial, sometimes suffrutescent, usually strigillose, sometimes glabrous; from a stout taproot. Stems many, ascending to erect, branched from base, 15–30 (–40) cm. Leaves 2.5–3.5 × 0.1–0.2 cm, rarely fascicles of small leaves present in nonflowering axils; petiole 0–0.1 cm; blade linear to narrowly linear-lanceolate, folded lengthwise, base long-attenuate, margins subentire or serrulate, apex acute. Flowers opening near sunrise; buds with free tips 0–0.5 mm; floral-tube 7 mm; sepals 4–6 mm, midribs keeled; petals yellow, fading yellow to orange, 15–20 mm; antisepalous filaments 5 mm, antipetalous filaments 2 mm, anthers 3–4 mm, pollen 90–100% fertile; style 10 mm, stigma discoid to quadrangular, exserted beyond anthers at anthesis. Capsules 18–20 × 2 mm, hard, dehiscent 1/2 their length, often tardily dehiscent throughout their length. Seeds oblanceoloid, 1–1.8 mm, sharply angled, apex truncate. 2n = 14.

Phenology: Flowering May–Sep.
Habitat: Gypsum outcrops.
Elevation: 500–1400 m.

N.Mex., Tex.

Discussion

Oenothera gayleana is a recently discovered gypsum endemic known only from scattered outcrops from De Baca and Eddy counties in New Mexico, and Culberson County in Texas. When published, the delimitation of O. gayleana included populations in Collinsworth and Dickens counties in the Texas panhandle, and adjacent Harmon County in Oklahoma. Subsequent study (B. Cooper et al., unpubl.) has determined they are actually O. serrulata.

Selected References

None.

Lower Taxa