Xanthoria aureola (Ach.) Erichs. forme saxicole de la zone mésique.

   Thallus loosely attached, placodioid-like and  spreading in patches, to 10-12 cm across. Thallus composed of loose lobes not overlapping, indented, strap-shaped, branched, thick, apices upturned, surface rough to embossed paper-like,  bright gold-yellow, yellow-orange, bright orange, conspicuous and distantly visible, without green tinge. Apothecia absent or rare and dispersed, disc concave, flat. Seems to be a coastal species stricto sensu, distributed in the mesi zone, immediatly above Caloplaca thallincola and Verrucaria (Hydropunctaria) maura. Compare this form of X. aureola with the two others described here and note that all intermediate specimen may be found. N.B. The highly coloured forms with thick, not strap-shaped lobes, erroneously have sometimes been described as Xanthoria calcicola Oxner but this species differs by its slightly verrucose or coralloid warted isidia. Worth also to mension: lobes, larger and thicker.