Chapsa

About

Chapsa is a genus of lichens in the family Graphidaceae. These lichens form thin, grey-whitish to pale olive crusts on tree bark and are characterized by fruiting bodies that start as slits but expand into round to angular discs level with the surface, each bordered by a pale rim. The genus has a pantropical to warm-temperate distribution, growing on shaded bark in humid lowland or foothill rainforests, with over 60 species that often serve as indicators of undisturbed forest habitats.

Summary from Wikipedia