Description: Crustose lichen: grey, brown or olive, smooth or lumpy forming tightly concentrated networks of dark-bordered, map-like mosaics. Discs minute, embedded in the bark, dot or fleck-like often in thin wavy lines. Mature shaded trees, waysides, woodlands, also on sheltered rock.

Key Identification Features:

• Densely mosaic-forming especially on heavily shaded or old tree bark
• Minute apothecia forming broken lines of dots and dashes like multiplying colonies of rod-shaped bacteria.

Original text submitted by Vince J. Giavarini

Distribution Map from NBN: Enterographa crassa at National Biodiversity Network mapping facility, data for UK.

iNaturalist: Enterographa crassa at iNaturalist World Species Observations database.