Description: This species inhabits the crystalline interstices of coarse siliceous rocks such as granite. The grey, virtually invisible, thallus and vague black prothallus means the shiny black discs stand out as the most conspicuous feature. The thick, notched, C- disc-rim or exciple is often suffused with red. The similar L. diducens has its exciple C+ carmine-red in section. In Ireland, the species has been recorded widely from granitic rocks. In var. brachyspora the grey thallus is easily conspicuous and the spores broader.

Key Identification Features:

• Thallus usually invisible, the prothallus reduced to a black smear; discs black with thickish, very conspicuous, usually reddened exciple which is C- in section
• In the crystalline crevices of granitic rocks.

Original text submitted by Vince J. Giavarini

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

iNaturalist: Lecidea auriculata at iNaturalist World Species Observations database.