The Arthoniaceae are a family of lichenized fungi in the order Arthoniales. Species have a widespread distribution, but are especially prevalent in tropical areas. Collectively, the family has a highly variable ecology, some species lichenized with green algae, and others lichenicolous—growing on other lichens. Species can grow on leaves, bark and rock. The genus was first described by Heinrich Gottlieb Ludwig Reichenbach in 1841.