Trimmatothelopsis americana

Trimmatothelopsis americana is a species of saxicolous (rock-dwelling) crustose lichen in the family Acarosporaceae. Originally described in 2011 as Melanophloea americana from Pennsylvania, it was reclassified in the genus Trimmatothelopsis in 2016 based on DNA sequence comparisons. The species is recognized by tiny black, dome-shaped apothecia (fruiting bodies) with small concave discs; under the microscope, asci contains hundreds of narrow ascospores, and it usually lacks an obvious thallus (lichen body). Known only from the Mid-Atlantic region of eastern North America, it grows on silica-rich (siliceous) rocks in humid riparian habitats, often in a narrow band just above the usual waterline, where floods periodically wet the rock....read more on Wikipedia.