This lichen grows on bark and forms a crust-like body (
thallus) up to across and 150–250
μm thick. The surface is white-gray and shiny, ranging from smooth to uneven or finely warty (irregularly ). No visible border zone () is present, though a thin, irregular black line may appear where the thallus meets neighboring lichens. In cross-section, the thallus has a firm outer skin (, 20–30 μm thick), an measuring 30–60 μm thick, and an inner tissue (
medulla, 100–150 μm thick) with clusters of
calcium oxalate crystals. The algal partner () is from the
green algal genus
Trentepohlia. The fruiting bodies are slit-like structures () that are wavy () and irregularly branched, partly protruding from the thallus () to prominently raised, and typically 3–10 mm long and 0.3–0.4 mm wide. They have a thin thallus-derived rim (), while the lips () are usually covered by a thin, non-algal, bark-like layer; the inner is hidden from view. The lips are distinctly grooved (striate) and black, but can appear dark gray because of the thin covering layer. The outer wall () is completely blackened () and deeply scalloped (crenulate) at the top, 70–150 μm wide, with an orange-brown inner portion. The spore-bearing layer (
hymenium) is 130–170 μm high and mostly clear, though the uppermost 20–30 μm is finely permeated with oil droplets (inspersed). The
asci are spindle-shaped (
fusiform, 120–150 × 20–25 μm), each containing (6–)8
ascospores. The ascospores are oblong, divided into 20–26 cells (19–25-
septate), 90–105 × 11–13 μm, and
stain violet-blue with iodine (I+ violet-blue). No
secondary metabolites were detected by
thin-layer chromatography. ==Habitat and distribution==