Protoparmeliopsis muralis (Pers.) M. Choisy var. versicolor

    Thallus placodioid, rosette-forming, 3-8 cm  diam., lobate, lobes 0.5-3 mm across, packed and merely leaving between them thin white lines (lobes distinct towards margins), upper surface smooth, wax-like, pale greenish, light green, grey-bluish, celadon, more dull whitish when dry, notably towards margins, strenghtening the rosette aspect; lower surface dull whitish to pale brown. Apothecia usually numerous, notably towards the center, masking thallus surface, markedly sessile when mature, disc flat, celadon, green-bluish, green, tinge with pink, pale  pink-ochre when old, exciple sometimes minutely crenulate, whitish, persistent. Ascospores ellipsoid, simple, colourless, 8-15 x 3-7 µm. C-, K- ou K+/- yellow, Pd- ou Pd+/- yellowish. On slightly acid or slightly calcareous rocks, more or less humid, nitrophile with oceanic trends. N.B. This taxon, is considered here on the basis of work of ancient authors and may not correspond to Protoparmeliopsis versicolor as accepted by Mediterranean authors.