Identificaciones de junior84

This flower is much smaller than the Hibiscus escobariae that grows in the same area. The photo with the one-dollar USA coin gives the sense of scale. Scanning other images for escobariae, I see one that is equally tiny. However, Junior84, whose knowledge is much more extensive, has an observation for Hibiscus-phoeniceus, and now I am leaning to the latter as a better identification. Thanks to anyone who can help clarify this identification.