A crustose lichen with a light grey, largely immersed thallus. The apothecia are oval when young, and become black and lirellate with age, following the grain of the wood.
Thallus: C-, K- or K+ yellow
Xylographa parallela is widespread in central and western Scotland where it is found on slowly decaying, decorticated wood and stumps of conifers. BLS distribution map
scottishlichens.co.uk 