Buellia dispersa

Buellia dispersa is a dull white to beige or dark brown crustose areolate lichen that grows on non-calcareous rock, such as basalt, granite and gneiss, in arid to semi-arid areas of northern Africa, Europe, and southwestern North America.[1][2] The areolas are distinct, becoming subsquamulose (lifting up at the edges) when separated and collecting in irregular patches, otherwise they form rosettes with lobed margins.[1] There is no prothallus.[1] It commonly occurs in the Mojave Desert, Channel Islands, and Santa Monica Mountains, also in the Cuyamaca Mountains, Santa Ana Mountains, and San Jacinto Mountains.[2] It is among he most common lichen species in the Sonoran Desert.