Acarospora is a genus of lichenized fungi in the family Acarosporaceae. Most species in the genus are crustose lichens that grow on rocks in open and arid places all over the world. They may look like a cobblestone road or cracked up old paint, and are commonly called cobblestone lichens or cracked lichens,. They usually grow on rock (are "saxicolous"), but some grow on soil (terricolous) or on other lichens. Some species in the genus are fungi that live as parasites on other lichens (lichenicolous fungi). Acarospora is a widely distributed genus, with about 128 species according to a 2008 estimate.