These form a thin crust on a substratum from which it is almost impossible to detach them. There are representatives of over 70 genera in New Zealand. The genus Lecidia has many species, also the genera Bacidia Arthonia, Buellia, Lecanora, Verrucaria, Rhizocarpon, and Lopadium are well represented here. Many indigenous species of Pyrenula are found on the trunks of forest trees.