Pyrenula perfecta

About

Pyrenula perfecta is a species of corticolous (bark-dwelling) crustose lichen in the family Pyrenulaceae. The species forms an extremely thin yellowish-gray crust on smooth bark and produces tiny hemispherical fruiting bodies 0.3–0.6 mm across with relatively large ascospores measuring 30–35 micrometres in length. It is known only from its type locality in scrubland along a creek in the southern Rupununi savannah of Guyana.

Summary from Wikipedia