Collemopsidium sublitorale

Collemopsidium sublitorale is a species of lichen in the family Xanthopyreniaceae. First described in 1871, it forms a "borderline" symbiotic relationship with cyanobacteria that is less structured than typical lichen partnerships. The species is characterised by an immersed thallus and black, roughly spherical fruiting bodies measuring 0.15–0.55 mm in diameter. It grows in the intertidal and littoral fringe zones of marine environments, exclusively on calcareous substrates such as limestone and marine shells. Studies have documented its presence...