Soil Paint Lichen

Acarospora schleicheri, the soil paint lichen, is a bleached to bright yellow areolate to squamulose lichen that commonly grows to 10 cm (4 in) on soil (terricolous) in arid habitats of southern California and Baja California, also in Europe and Africa.:218 It produces rhizocarpic acid as a secondary metabolite, which gives it a yellow coloration and serves to protect it from the sun. Its lower surface is also yellow. It can be greenish when moist. Roundish, angular, or...