Here’s Mentzelia (or Nuttallia) nuda, a biennial that’s common in sandy places on the Great Plains. The flowers open in the late afternoon.
I tried to take a picture at 10 p.m. last night but discovered that taking pictures of a flower you can’t see is not very productive. I knew where it was, sort of, but not exactly, and in the process also discovered that using the flash to help find the flower does not result in a clear picture. When I finally got a fairly acceptable picture, I noticed there was a gigantic earwig right in the middle of the flower.
This one is certified earwig-free.
the miserable gardener 
What I assumed was Mentzelia nuda native to my property is extremely perennial: is there a biennial look alike? Your plant doesn’t look quite like decapatala (petal number is right)…which is biennial and denies me. Oh well….
I got these from Harlequin’s a few years ago, and planted them in my sandpile. Flowers are about two inches across, max. They look like the ones the grow, or used to grow, in the sand on Hwy 85 south of the railroad tracks at the west end of Highlands Ranch. Ipomoea leptophylla, too. The cellular monopoles on the east side of the highway are anchored in bedrock 33 feet down in the sand, or so I heard.
This is an off year for Mentzelia decapetala. I see only one plant. I sowed seed from last year’s extravaganza but not much happened.
Off year for Abronia fragrans, too. The plants are still alive, but decided not to bloom, for some reason. Probably not enough water in spring.
The list of plants that can be grown in sand is surprisingly large.
Bob