Description: This form has all the features of V. macrostoma (described elsewhere) but differs in the absence of spherical discs (perithecia), and in the presence of sorediate or isidia-like structures (blastidia) growing along the edges of the areoles (cracked pieces of the thallus).

Key Identification Features:

• Thallus immersed, discs and dots (pycnidia) visible at the surface, speckled with fragments of grey or brown from below
• Discs with distinct sunken apex; hard limestone.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Verrucaria macrostoma f. furfuracea at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Verrucaria macrostoma f. furfuracea at iNaturalist World Species Observations database.