Rhizocarpon reductum

Rhizocarpon reductum  is a very common crustose lichen which occurs on gravestones and smooth, wel lit siliceous rocks. The grey, cracked thallus is often covered in small black apothecia. It is probably under recorded in West Glamorgan.

Listed under Rhizocarpon concentricum by Alan Orange in Flora of Glamorgan (Wade et al, 1994).