Gyalectidium denticulatum

About

Gyalectidium denticulatum is a species of lichen-forming fungus in the family Gomphillaceae. It is a leaf-dwelling lichen known from Central and South America, including Costa Rica, Brazil, and Argentina. The species is distinguished by its distinctive reproductive structures, which form small crater-like depressions surrounded by a ring of tooth-like segments, a feature that separates it from the similar-looking Gyalectidium caucasicum.

Summary from Wikipedia