Lithothelium

Lithothelium is a genus of lichen-forming fungi in the family Pyrenulaceae. Most of the species are found in tropical climates, and are usually corticolous (bark-dwelling) or saxicolous (rock-dwelling). These lichens form thin, crust-like layers that are often embedded within their substrate and are characterized by distinctive black, flask-shaped reproductive structures that may occur individually or in fused clusters with small openings for spore release. Established as a genus in 1885 by the Swiss botanist Johannes Müller Argoviensis, Lithothelium species can be distinguished from similar lichens by their rounded spore compartments and the presence of specialized structures called ocular chambers that assist in spore discharge....read more on Wikipedia.