parmelia quercina

Description:

Liche foliose of grey color, very much adhered to the substrate and often with abundants bluff-reddish apothecia, big and disk shaped. It can be up to 15 cm in diameter. Underside is dark getting paler close to the margins

Habitat:

It is one of the first lichens colonizing new surfaces. Generally on tree barks rich in nutrients, specially on planifolia, in very well illuminated places, and moderate humidity. Very common in south Europe. This one was found on the bark of a Holm oak