Cactus and Biological Soil Crust
Like other desert areas in the southwest, Dinosaur National Monument has large sections of biological soil crust. These crusts include various forms of algae, bacteria, moss, lichens, fungi and liverworts. They're easily damaged, so don't step on them.
These soils provide a foundation for plants, such as the cactus I haven't yet identified here.
Imaged May 2011 on the Mitten Park Trail.