[2] The order includes seven families (Andreiomycetaceae,[4] Arthoniaceae, Chrysotrichaceae, Lecanographaceae, Opegraphaceae, Roccellaceae and Roccellographaceae).

[6] Andreiomycetaceae Chrysothricaceae Rocellaceae Opegraphaceae Rocellographaceae Lecanographaceae Arthoniaceae Curvularia brachyspora Cudonia circinans Seynesia erumpens Figure 1.

Cladogram of the Arthoniales, rooted with Curvularia brachyspora, Cudonia circinans and Seynesia erumpens as the outgroup.

The order has adapted to live in both humid forests and dry habitats like savannas and steppes, as well as varying altitudes from sea level to alpine regions.

[8][9] The species diversity of the Arthoniales is expected to be higher than currently reported from several areas worldwide like the tropical rain forests.

The reason is that the Arthoniales is an old order and taxa have evolved in parallel for a long time, which gives a high level of homoplasy.