Gaura demareei P. H. Raven &D. P. Gregory, Mem. Torrey Bot. Club 23(1): 78, figs. 21, 54. 1973

Herbs usually robust winter-annual, sometimes biennial, densely strigillose throughout; from fleshy taproot. Stems usually well-branched distal to base, 50–400 cm. Leaves in a basal rosette and cauline, 3–7 × 0.2–0.8 cm; blade narrowly elliptic to elliptic or lanceolate, margins subentire or shallowly undulate-denticulate. Flowers 4-merous, zygomorphic, opening at sunrise; floral tube 4–13(–15) mm; sepals 13–20 mm; petals white, fading pink, rhombic-obovate, 10–17 mm; filaments 8–17 mm, anthers 3–7 mm, pollen 90–100% fertile; style 18–32 mm, stigma exserted beyond anthers at anthesis. Capsules ellipsoid or ovoid, sharply 4-angled, 4.5–7 × 1.5–2.5 mm; sessile. Seeds 2–4, yellowish to reddish brown, 1.2–3 × 0.7–1.3 mm. 2n = 14.

Flowering Jul–Oct. Open meadows in sandy loam; 70–200 m; Ark.

Oenothera demareei is known only from Clark, Garland, Hempstead, Howard, Montgomery, Pike, Saline, and Sevier counties.

P. H. Raven and D. P. Gregory (1972[1973]) found Oenothera demareei to be self-incompatible.