Oenothera caespitosa

Beautiful and drought resistant plant for full sun. Rare.

Tufted evening primrose. Rare. The desert evening primrose forms tight rosettes and big white flowers when it wakes up from its summer dormancy. A taproot aids survival. Each large, white flower has four, heart-shaped petals and eight yellow stamens. The flowers open in late afternoon, close the next morning, and wither to pink or red-violet. Lateral roots may give rise to new perennial plants. Up to 40cm. Hardy in the extreme.

Evidently it was the scent that reminded botanists of the english primrose.  From the North America and South America in the temperate regions. 

BLM Nevada, CC BY 2.0 <https://creativecommons.org/licenses/by/2.0>, via Wikimedia Commons

And in a garden... English:  Jacob W. Frank, Public domain, via Wikimedia Commons