The Prairie Blazing Star is abundant in the plains around Denver and to the east. Often found on roadsides and disturbed sites. One of the unsusall things to me is that they are typically bat pollinated but grow in areas where there are not caves to safe house the bats. Flowers are only open during the night losing all the petals not long after sunrise. That makes getting nice photos difficult. This is taken at the Denver Botanic Gardens growing with Cylindropuntia imbricata
The comparatively large, glossy flowers of this genus are all the more striking for often being produced in barren, sere habitats.