Mentzelia decapetala

Mentzelia decapetala, commonly known as tenpetal blazingstar, evening-star, or ten petaled western star is a biennial or short-lived perennial with large white flowers that bloom at night. It is native to dry areas of the western Great Plains in the United States and southern Canada. Its scientific name and many of its common names refer to the apparent ten petals of the flowers, the only species in the blazing star genus with such wide staminodes. ...read more on Wikipedia.