Gaura boquillensis P. H. Raven & D. P. Gregory, Mem. Torrey Bot. Club 23(1): 21, figs. 3, 33. 1973

Herbs perennial, strigillose and glandular puberulent; from a narrow taproot. Stems erect, usually branched several cm belowground or near base, sometimes also branched distally, 25–100 cm. Leaves in a basal rosette and cauline, basal 1–6.5(–13) × 0.4–1.5 cm, blade narrowly oblanceolate; cauline 0.5–3(–6.5) × 0.1–1.1 cm, blade very narrowly elliptic, narrowly lanceolate, or linear, margins sinuate-dentate to subentire. Flowers 4-merous, slightly zygomorphic, opening near sunset; floral tube 3–8.5 mm; sepals 3–9 mm; petals white, fading pink to red, slightly unequal, elliptic-obovate, 4–10 mm, clawed; filaments 2–4.5 mm, anthers 2–4 mm, pollen 85–100% fertile; style 6.5–15 mm, stigma exserted beyond anthers at anthesis. Capsules erect, sometimes reflexed in age, fusiform, sometimes slightly narrowed in proximal 1/3, 5.5–13 × 1–2.5 mm, valves with inconspicuous raised midrib; sessile. Seeds (1 or)2–4, yellowish or light brown, 1.5–2.5 × 0.8–1.3 mm. 2n = 14.

Flowering May–Aug. Washes, sandy canyon sides; 600–1400 m; Tex.; Mexico (Chihuahua, Coahuila, Nuevo León).

Oenothera boquillensis has a narrow distribution in canyons from near the Rio Grande River in southern Brewster County southward into Mexico from central Chihuahua, Coahuila, and western Nuevo León. P. H. Raven and D. P. Gregory (1972[1973]) determined O. boquillensis to be self-incompatible.