Picture taken on the 1st July 2007 at Aiguablava, Costa Brava, Girona, on a wall with calcareous stones, 20 m. altitude.
A very common nitrophilous lichen.
Corticolous and saxicolous, foliose thallus, with rizhinae, very variable in colour,but more or less gray with blue or green tinge, with pruina, and a lot of soredia.
Easy to mistake with other Physconia and even with Physcia caesia.
Genus Physconia needs further studies because there are some species that are not very homogeneous.