Galapagos Species Database

Thallus thin, often partially embedded in the bark, continuous to rimose, pale creamy white, grayish or ochraceous, ± the same color as the substrate; surface smooth to ±verrucose, not pruinose; Apothecia immersed, lirellate, immature ±fissurine, but disc soon expanded; lirellae ±narrow, short to ±elongate, sparsely branched, but often ±stellate, occasionally within slightly paler stromatic thallus areas; labia thin, narrow or absent, typically with a prominent thalline rim; disc expanded, barely concave to flattened, with a white, farinose pruina; exciple thin, indistinct or almost absent, basally not expanding with age, not carbonized; hymenium hyaline, clear (not inspers, but occasionally with few, sparse oil droplets), I–; ascospores pale gray, soon brownish, I+ red or reddish brown, 8 per ascus, ellipsoid to narrowly ellipsoid, 14-25 x 6-10 µm, submuriform, 4-6 vs. 1-2 celled. Chemistry: Norstictic and connorstictic acid, K+ orange-red (crystals).

The species is superficially similar to P. intricans, but the lirellae, although surrounded by a thalline rim, are typically not embedded in a distinct stroma. Young lirellae may appear fissurine, but the disc soon expands. Most diagnostic are the short, ellipsoid, submuriform spores.