Oenothera breviflora Torrey &A. Gray, Fl. N. Amer. 1: 506. 1840; Camissonia breviflora (Torrey & A. Gray) P. H. Raven

Herbs densely to sparsely strig­illose, sometimes also short-hirtellous, the hairs spreading or appressed; taproot deep, woody with numerous slender branches in age, producing multiple rosettes. Leaves 1.7–12 × 0.3–3.3 cm; petiole not winged, 1.5–3 cm; blade very narrowly elliptic, base attenuate, margins irregularly pinnatifid, apex acute to long-acuminate. Flowers opening near sunrise; floral tube 1.8–2(–2.5) mm, glabrate to very sparsely pilose inside near base; sepals 3–6(–7.5) mm; petals yellow, 5–7(–9) mm; episepalous staminal filaments 2.8–4(–5) mm, epipetalous ones 1.5–1.8(–2) mm, anthers 0.9–1.3 mm; sterile prolong­ation of ovary 4–15 mm, style 3–6.5 mm, sparsely pilose near base to glabrate, stigma surrounded by anthers of longer stamens at anthesis. Capsules subterete, cylindric-ovoid, often slightly asymmetric, 8–17 × 2–5 mm, walls thick, evidently distended by seeds; sessile. Seeds tan to brown, curved-cylindric, 1.3–1.8 × 0.7–0.9 mm, pitted in rows. 2n = 14.

Flowering Jun–Aug. Seasonally moist meadows, dry streambeds, edges of drying ponds, mountains and upper foothills; 100–3100 m; Alta., B.C., Sask.; Colo., Idaho, Mont., Nev., Utah, Wyo.

P. H. Raven (1969) determined that Taraxia breviflora is self-compatible and primarily autogamous.