Nigrovothelium bullatum

Nigrovothelium bullatum is a species of lichen-forming fungus in the family Trypetheliaceae. The lichen forms an olive-green to olive-brown crust on tree bark with a conspicuously blistered and warty surface texture that distinguishes it from related species. Its reproductive structures are small, black, densely arranged bodies that sit exposed on the lichen surface with separate ostioles appearing as tiny black dots. The species is found in tropical and subtropical regions of Asia, including India, Thailand, and Vietnam, where it grows on sun-exposed bark in fairly dry habitats....read more on Wikipedia.