Melanelixia subaurifera (Nyl.) O. Blanco & al.
Melanelia subaurifera (Nyl.) Essl.
Thallus foliose, rosette-forming, 2-8 cm diam., lobes indented, 3-5 mm wide, tightly appressed to the substratum, upper surface brown-greenish, bronze tinged copper-coloured, covered with globose isidia, denser towards the center, evolving into soredia, pale yellowish, distinctly visible when eroded, lower surface brown-blackish with simple rhizines. Apothecia rare or absent, 1-2 mm diam., exciple sorediate. Ascospores colourless, simple, broadly ellipsoid, 9-12 x 6-7 µm. Photobiont: trebouxioid. Cortex : K-; medulla: C+ red, KC+ red, K-, Pd-. Species not very rare on horizontal branches of deciduous trees, rarer on rocks except in maritime areas where it is not rare in this situation, can also be found on artificial substrates such as painted wood or plastics, in especially shipwrecks, see Melanelixia subaurifera forme sur substrats artificiels.