Roccellaceae Dendrographa decolorans (Schismatomma decolorans) Growth type crustose Chemical results negative. UV- or UV+ white Can form large patches on dry, shaded bark of old, rough-barked deciduous trees. Tolerates relatively high levels of nitrogen enrichment. Thin whitish, lilac-grey or pinkish-grey thallus (scratching yellow-orange), often with grey-black prothallus. Punctiform mauve-grey soralia spread to +/- cover thallus. Apothecia and pycnidia are rare. Similar: Thallus of sterile Arthonia pruinata is C+ red. Enterographa sorediata has a waxier thallus and paler soralia. P+ rust-red

Dendrographa decolorans (Schismatomma decolorans)
Holton Lee, Dorset. March 2013