A pale greyish to buffish cructose lichen, which is thin to cracked aerolate. Apothecia absent.
Found on silica-rich rock, especially outcrops that get wet and dry out fairly quickly. Locally common and widespread in the north and west.
Photographs of Pertusaria aspergilla, taken March 2012 on local Bunter Sandstone outcrop, Staffordshire. © Pete Hillman 2012. Camera used Panasonic Lumix DMC-FZ38.