Roccellaceae Enterographa crassa Growth type crustose. Chemical reactions negative but K/UV+ mauve Common in southern England on shaded trees, occasionally on damp, sheltered rocks Smooth or lumpy, grey, brown or olive-green thallus with black prothallus, often forming mosaics. Minute dark-brown, embedded apothecia (0.1-0.3mm) forming thread-like lines or dots. Asci 8-spored, the spores 5-7 septate, 28-38 x 4-6 µm. Microscope photographs below. Similar: Enterographa hutchinsiae has larger, comma-like or lirelliform, often branched apothecia. Usually found on damp, vertical siliceous rock faces but can occur smooth-barked trees (e.g. Holly and Beech)

Microscope photographs



Enterographa crassa
Holton Lee and Badbury Rings, Dorset. December 2012, 2015