Gaura parviflora Douglas ex Lehmann, Nov. Stirp. Pug. 2: 15. 1830, not Oenothera parviflora Linnaeus 1759; G. australis Grisebach; G. hirsuta Scheele; G. micrantha (Spach) D. Dietrich; G. parviflora var. lachnocarpa Weatherby; Schizocarya micrantha Spach 1835, not O. micrantha Hornemann ex Sprengel 1825

Herbs annual, strigillose, glandular puberulent, and long-villous; from heavy taproot, 2–4 cm diam. Stems erect, unbranched or many-branched distally, (20–)30–200(–300) cm. Leaves in a basal rosette and cauline, basal 4–15 × 1.5–3 cm, petiole 0–1.8 cm, blade broadly oblanceolate, margins sinuate-dentate to dentate; cauline 2–13 × 0.5–5 cm, petiole 0–2 cm, blade nar­rowly elliptic to narrowly ovate, margins sinuate-dentate to dentate. Inflorescences relatively long, dense. Flowers 4-merous, nearly actinomorphic, opening near sunset; floral tube 1.5–5 mm; sepals 2–3.5 mm; petals white, fading pale to dark pink, slightly unequal, oblong-obovate to elliptic-oblanceolate, 1.5–3 mm, abruptly clawed; filaments 1.5–3 mm, anthers 0.5–1 mm, pollen 85–100% fertile; style 3–9 mm, stigma surrounded by anthers at anthesis. Capsules fusiform, terete, weakly angled in distal 1/3, angles becoming broad and rounded in proximal part, 5–11 × 1.5–3 mm, tapering abruptly toward base; sessile. Seeds 3 or 4, reddish brown, 2–3 × 1–1.5 mm. 2n = 14.

Flowering (Feb–)Apr–Oct. Rocky prairie slopes, woodlands, along streams, roadsides, disturbed areas; 10–2800 m; Ala., Ariz., Ark., Calif., Colo., Fla., Ga., Idaho, Ill., Ind., Iowa, Kans., Ky., La., Md., Mass., Minn., Mo., Mont., Nebr., Nev., N.Mex., Okla., Oreg., S.C., S.Dak., Tenn., Tex., Utah, Va., Wash., Wyo.; Mexico (Baja California, Chihuahua, Coahuila, Durango, Nuevo León, Sinaloa, Zacatecas); introduced in South America (Argentina), Asia (China, Japan), Australia.

Oenothera curtiflora is self-compatible and autoga­mous (P. H. Raven and D. P. Gregory 1972[1973]). Sometimes it is apparently a biennial. The species is native to grassland regions and open areas across much of interior North America. The full extent of its indigenous range is not clear and collections from the eastern half of the United States (Alabama, Florida, Georgia, Indiana, Massachusetts, and Tennessee) and California may be more recent introductions. Gaura mollis Nuttall ex Torrey 1827 is an isonym of G. mollis E. James 1822, a suppressed name.