Picture taken on the 20th April 2008 at Talló, Bellver de Cerdanya, Baixa Cerdanya, Oriental Pyrenees, catalonia, on a wall, well-lit place.
Squamulous thallus, convergent, covering several centimeters, colour from white to green-brown, very variable, squamules adpressed to substrate, irregular in form, overlapping each other, glossy when wet.
Apothecia, 0,2-0,8 mm in diameter, disc from rose to dark brown, dark red when wet, flat or convex.
It is a common lichen growing on siliceous rocks, frequent in Talló.
See: UK Lichens by Mike Sutcliffe
Some descriptions are not the same. The genus Trapelia needs further studies and I introduce a ? to this determination.