Superficial mycelium initially conspicuous, forming a dense contorted reticulum; dark brown, composed of hyphae 3-3.5 µm diam., markedly constricted at the septa, branched (often more or less rectangularly) and anastomosed; degenerating (probably as the host cortex breaks down) and becoming rather inconspicuous. Anamorph: unknown. Teleomorph: ascomata perithecia, (40–) 45–50 µm diam., black, subglobose to somewhat conical above, smooth-walled, sessile to half-immersed in the host lichen, scattered; with an ostiole 8–10 µm diam. surrounded by short dark brown blunt-tipped hyphal cells. Peridium dark brown above and ± hyaline below, composed of a few layers of flattened angular cells 4–6 µm diam., overgrown by vegetative hyphae. Interascal tissue absent. Asci 17-28 × 10.5-13.5 µm, broadly pyriform, ± sessile, fissitunicate, strongly thickened above and with a distinct ocular chamber, not staining in iodine, 8-spored. Ascospores arranged biseriately, (8·5–) 9-11.5 (-11.8) x 2.6-3.3 (-3.5) µm, clavate to narrowly obovoid, usually with a wider and sometimes slightly shorter upper cell, occasionally located upside down in the ascus, 1-septate, slightly constricted at the septum, hyaline, smooth-walled, when overmature pale to medium brown and with a rough wall, perispore not seen.