Thalli scattered on the leaf surface, well-developed around the ascomata, thin, diffuse, greenish grey, composed of hyaline interwoven hyphae 3–4 μm diam. Photobiont chlorococcoid.
Anamorph: not known.
Teleomorph: ascomata perithecia, 100–200 (–250) µm diam, to 100 µm high, sessile, subglobose to hemispherical with a flattened to depressed top, greyish brown to dark brown, the outer wall with a felted aspect. Involucrellum absent. Excipulum 18–32 μm thick; outer layer olivaceous brown, 10–20 μm thick, composed of 1–2 rows of globose cells; inner layer composed of textura angularis, hyaline to pale brownish, 8–12 μm thick. Interascal tissue absent. Periphyses 6.5–12 × 3.5–5 μm, colourless. Asci 40–60 × 15–20 (–25) μm, clavate to obovoid, ascus apex slightly thickened, J–,protoplasm J–, 8-spored. Ascospores (16–) 20–35 (–40) × 4.5–9 (–10) μm, ellipsoidal to fusiform, the ends rounded, straight to slightly bent, submuriform, with (3–) 5–9 transverse septa and 1–6 longitudinal septa except in the apical cells, slightly constricted at the septa, occasionally transversely septate only, 3–5 times as long as broad.
Differs from P. inexpectata in the larger ascospores which are 5- to 9-septate and often submuriform.
Associated with chlorococcoid algae, but possibly not truly lichenized; found on long-lived leaves. In GB&I, associated with Hedera hibernica.
In GB&I, known from England (Glooucestershire) and Wales (Glamorgan); elsewhere reported from Spain.