Oenothera psammophila
St. Anthony Evening Primrose; St. Anthony Sand-lily

Illustration by Robin A. Jess. Reprinted with permission from Intermountain Flora: Vascular plants of the Intermountain West, U.S.A., by A. Cronquist, N. H. Holmgren, and P. K. Holmgren, Vol. 3A Subclass Rosidae (except Fabales), p. 211, copyright 1997, The New York Botanical Garden.