Blackbush scrub

Blackbush scrub, or blackbrush scrub, is a vegetation type of the Western United States deserts characterized by low growing, dark gray blackbush ("Coleogyne ramosissima") as the dominant species. Blackbush often occurs in pure stands, giving a uniform dark gray appearance to the landscape. 
Mojave Desert.
Blackbrush scrub occurs over a wide elevation range in the Mojave Desert. It may occur as an understory in Joshua tree woodland or pinyon-juniper woodland. Associates in the Mojave Desert include ephedra ("Ephedra nevadensis", "Ephedra viridis"), hop-sage "Grayia spinosa", turpentine broom ("Thamnosma montana"), horsebrush ("Tedradymia spp."), cheesebush ("Ambrosia salsola"), and winter fat ("Krascheninnikovia lanata").
Colorado Plateau.
In the Colorado Plateau, it occurs across uniformly thin soils. 