The lichen has a thin, whitish-grey to greenish-grey, effuse (spread-out) thallus. Its apothecia are more or less spherical to barrel-shaped, measuring 0.4–0.7 mm in diameter. The pale pink excipulum, initially closed, later opens via a ragged pore (ostiole). Ascospores typically number eight per ascus (sometimes only four are present), and are hyaline, halonate, and measure 90–130 by 9–12 μm.[2]
Topeliopsis decorticans appears to be morphologically identical to T. acutispora; the two species are distinguished by major differences in their ascospores, including shape, size, septation, and number per ascus.[3]
