Pseudoschismatomma rufescens

Thallus thin, smooth or finely rimose-cracked with white dotting (either hyphal bundles or crystalline deposits), sometimes delimited by a dark prothallus and mosaic-forming, dull olive to red-brown, rarely grey. Apothecia (0.25–) 0.32–0.5 (–1) × 0.09–0.15 (–0.3) mm, immersed, sometimes elevated on a thalline cushion, curved or substellate, usually numerous and often contiguous; disc fully exposed, surrounded by a very thin exciple (K–) and sometimes a thin persistent whitish raised pseudothalline exciple formed from aggregations of the thalline dots; exciple K–; epithecium brown; hymenium 50–60 µm tall, K–. Ascospores 3-septate, (15–) 17–27 × 3–5 µm, fusiform, often curved, without a gelatinous sheath. Conidia 4–8 × 0.8–2 µm, variable, straight or curved. Thallus C–, K–, KC–, Pd–, UV– (no lichen products detected by TLC).

Characterised by the small, immersed, often slightly raised apothecia with a fully exposed disc, thin true exciple that is often surrounded by a thin whitish pseudothalline margin, and curved, fusiform ascospores. P. rufescens resembles the rare Schismatomma ricasolii, but the true exciple of the former species is always clearly visible in sections and the ascospores are shorter.