Description from Cannon et al (2021) below.
Thallus thin to thick, pale grey to pale green-grey, continuous, often fissured; prothallus indistinct; soralia mostly delimited, rounded, convex, rarely excavate, to 1.5 (–3) mm diam., occasionally fused; soredia white, coarse. Apothecia rare, developing within soralia, disciform, single-pored; disc pale pink, to ca 0.7 mm diam. Ascospores 6 per ascus, 18–20 × 10–14 um; Thallus C–, K+ brownish, Pd+ red (fumarprotocetraric, protocetraric and succinprotocetraric (trace) acids).
Pertusaria pupillaris, from similar habitats, is ± immersed in bark and lacks succinprotocetraric acid. Lepra amara has KC+ violet soralia and a very bitter taste.
On old Pine lignum, in Caledonian Pine forest
![Key to map date classes](/sites/default/files/default_images/species-maps-key_2.png)
Rare, Scottish Highlands
Confined to well lit dead wood in native pinewoods, where it may be vulnerable to overgrowth and shading by coarse vegetation if grazing levels are greatly reduced.
Britain: Notable & International Responsibility species
Scotland: Priority Taxon for Biodiversity in Scotland
Cannon, P., Kukwa, M., Coppins, B., Fletcher, A., Sanderson, N. & Simkin, J. (2021). Pertusariales: Ochrolechiaceae, including the genera Lepra, Ochrolechia and Varicellaria. Revisions of British and Irish Lichens 5: 1-17. Link