Buellia saxorum forme pycnidiée

     This form, quite frequent, comes, under or on, the siliceous rocks at the edge of the sea (but not too acidic, for example the Armorican sandstone) very in the shade and never receiving the sun. The fairly thick thallus looks like a slightly cracked enamel paint, whitish tinged with bluish gray, glaucous gray, yellow gray, pink, purplish, etc. (typically pastel colorings) and has no apothecia (or very few and poorly developed) but only very many black pycnidia which gives it a dotted appearance. Can form mosaics with itself or with other species well separated by a black hypothallus.