Verrucaria fusconigrescens

In Britain Verrucaria fusconigrescens is a northern and western coastal specie of siliceous rocks, or slightly calcareous rocks inland. The brown, areolate thallus is well-developed, becoming rimose, sometimes locally pruinose. Areoles are matt, plane to irregularly clavate structures. The prothallus is dark brown to blackish. Perithecia are immersed in the thallus, but can form moderate projections uncovered by a thalline layer and with an inconspicuous ostiole.

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