Shrubby formations of the western Mediterranean basin, mostly meso-Mediterranean, but often also thermo- or supra-Mediterranean, dominated by the low, calciphilous Cistus albidus or Cistus clusii, or occasionally by indifferent species, usually accompanied by a more varied flora than that of the silicicolous cistus maquis, though sometimes capable of forming dense cistus fields. These can be identified by use of digit 1 in the fourth decimal place, digit 2 being reserved for more varied formations.