Acrocordia

Acrocordia is a genus of lichen-forming fungi in the family Monoblastiaceae. These lichens form thin, whitish to pale grey crusts on tree bark and rocks, appearing as scattered black dots where their tiny flask-shaped reproductive structures emerge from the surface. The genus includes nine species found in various parts of the world, typically growing in mildly alkaline environments on broad-leaved trees or damp, mineral-rich rock faces. ...read more on Wikipedia.