Northern Prairie Wildlife Research Center
Sometimes called "pale evening primrose," prairie evening primrose is restricted to the western third of North Dakota. Elsewhere, the plant ranges from Montana and Utah south to Mexico at elevations below 8,000 ft.
This is the only annual, white-flowered evening primrose that occurs in North Dakota. Stems are simple or branched above and covered with a white, shiny skin. Lower leaves are about 3 inches long and have long stalks (petioles), whereas upper leaves are shorter and may attach directly to the stem. Flowers are about 2 inches wide. Fruit is a ribbed capsule up to 1 1/2 inches long that contains yellowish-brown seeds.
Look for prairie evening primrose after late May in sandy native prairie that is lightly or moderately grazed by cattle. Some of the biennial and perennial Oenotheras are used as foods and medicines, but I could find no mention of O. albicaulis in this regard.
This plant belongs to the evening primrose family (Onagraceae) which contains about 600 species including the ornamental fuchsias. Flowers in this family generally open in late afternoon or evening for pollination by night-flying insects. The names Onagra and Oenothera stem from a name used by the Greek intellectual Theophrastos (370-285 B.C.) for the fireweeds that are also members of this family. The specific name albicaulis means "white-stemmed" in botanical Latin.
Prairie evening primrose was first described for science in 1816 by the eminent German botanist who settled in Philadelphia, Frederick Pursh (1774-1820). He was the first to publish on the many new plants collected by the Lewis and Clark Expedition of 1804-1806.