Melanelixia subaurifera  

Thallus 0.5-5(-10) cm diam., often rosette-forming, thin, closely appressed centrally but often free at margins. Lobes to 5 mm wide, flat or occasionally with lobe apices ± upturned, irregular, radiating, contiguous, sometimes overlapping, the margins crenate or irregularly incised. Upper surface brown to green-brown or with a reddish tinge, matt or rarely shiny in parts (particularly towards the apices), faintly to extensively pitted or ridged, isidiate-sorediate. Isidia globose, cylindrical or irregular, soft, secondarily derived from soredia by partial cortication, leaving a pale yellow (subauriferin) area where abraded. Medulla white. Lower surface dark brown to black, with simple concolorous.
Anamorph: pycnidial, with conidia 5.5-7 x ca 1 µm in size.
Teleomorph: ascomata apothecia, rare, to 2 mm diam., the thalline exciple margin sorediate. Ascospores 9-12 × 5.5-7 μm.
Chemistry: cortex K–, N–; medulla and soredia C+ red, K–, KC+ red, Pd–, UV– (lecanoric acid and subauriferin).