The lichen body (thallus) is a thin, whitish, crust-like growth that spreads across the bark and can disrupt the bark surface; in cross-section it is about 30–50
μm thick. The surface shows fine cracks and is bordered by brownish boundary lines (). The algal partner () is indistinct but is thought to be the green alga
Trentepohlia; its cells are about 10–14 × 7 μm. The fruiting bodies (
ascomata) are scattered and broadly protruding from the bark (), usually roundish to spot-like, about 0.25–1.25 mm across and 75–120 μm thick in cross-section. They sit level with the thallus and are often partly covered by bark fragments. The surface of the fruiting bodies is crimson-red and frosted with pigment (), with areas above mature spore-bearing structures (
asci) turning brownish. The red pigment occurs as fine crystalline grains that can clump together into larger aggregates. Under the microscope, the uppermost tissue layer () is densely pigmented and water-repellent (
hydrophobic, about 25–40 μm thick), and the asci are more or less dispersed, spherical to nearly spherical ( to subglobose, about 77–90 × 45–60 μm) with a distinct stalk. The
ascospores are persistently colorless (
hyaline) and divided by both transverse and longitudinal cross-walls (), measuring about 30–40 × 14–19 μm, with roughly nine transverse cross-walls and 1–3 longitudinal cross-walls per segment; the pattern of division can be irregular. In chemical reactions reported from microscopic preparations, the red pigments dissolve in KOH and shift to a purplish-orange tone, and iodine reactions are described for gels and ascus/spore structures. ==Habitat and distribution==