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(Map updated: 11 August 2009)

This lichenicolous lichen inhabits the thallus of Lecanora polytropa but is also suspected on other species. The pure black discs grow both on the thallus and also the discs of the host. In a squash of C. supersparsa the contents show up bright blue-green. Spores are 8–13 x 5–7µm, slightly peaked at the ends. Look for it on hard acid rock in former mine sites.

Key characteristics

• Growing on the thallus and discs of Lecanora polytropa; discs coal-black, internally, with blue-green pigments
• Highly acidic nutrient-impoverished rocks, for example, mine spoil.

NBN Atlas mapping: Species account : NBN Atlas UK Species Observations database

iNaturalist: Species account : iNaturalist World Species Observations database

Original text submitted by Vince J. Giavarini