A crustose species that forms a pale, leaden grey thallus. Perithecia are immersed in the thallus and visible as black dots inside small pale units which are separated by dark lines.
In Scotland, Placopyrenium fuscellum mainly occurs along the coast and in the south where it is found on basic rocks, including coastal rock and gravestones. BLS distribution map
Placopyrenium fuscellum is often found growing parasitically on Verrucaria nigrescens.
scottishlichens.co.uk 