Duration: Annual Nativity: Native Lifeform: Forb/Herb General: Annual in basal rosette, nearly stemless or often developing stout leafy stems 10-20 cm; thick taproot; dense pubescence of spreading papillate-based white hairs. Leaves: Blades 5-27 cm, larger ones 3.5-7 cm wide, mostly pinnatifid into toothed or rounded lobes, narrowed to long, winged petiole expanded at very base. Flowers: Yellow, petals 3.5-5.5 cm, notched at apex; opening at dusk closing the following morning. Fruits: Ovary and capsule densely hairy with spreading white hairs; capsules 2.8-4.5 cm long by 6.5-7.5 mm wide at base, thick and woody, upright, straight, 4-angled, tapering to conspicuously narrowed tip. Ecology: Found on sand flats, playas, gravelly-sandy washes, common but not very abundant below 4,500 ft (1372 m); flowers March-May. Distribution: s CA, NV, s UT, AZ, NM, s TX; south to c MEX. Notes: Plants are easy to know by being annual, their caespitose, acaulescent habit, pinnatifid leaves. sepals 15-28 mm, yellow flowers and terete fruits without strong angles or wings., Ethnobotany: Dried flowers used for ceremonies and poultice applied to swellings. Etymology: Oenothera is from Greek oinos, wine and thera, to imbibe, while primiveris refers to spring. Synonyms: None Editor: SBuckley 2010, FSCoburn 2015