Description: Like A. smaragdula (described elsewhere) but with a wide-spreading, smooth, evenly-cracked crust (K-) thinning towards the margin (never lobe-like), of dull or dark brown colour. Discs deeply concave. Look for it on sandstone or other coarse-grained siliceous rocks.

Key Identification Features:

• Smooth, dark brown, wide-spreading evenly-cracked thallus (K-)
• Discs deeply concave; on gritty, acid rock.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Myriospora rufescens at iNaturalist World Species Observations database.