Fuscopannaria rugosa is identifiable by its foliose-squamulose thallus, which has longitudinal wrinkles on the upper surface.

It also has a distinct hypothallus, a relatively thick algal layer, and a cortex made up of thick-walled cells in both the thalline and apothecial structures.

It produces simple, hyaline ascospores that have a smooth, pointed tip (epispore) at their apex.

[2] Fuscopannaria rugosa forms circular clusters with fan-shaped lobes that are up to 4–5 cm (1.6–2.0 in) in diameter.

The lichen has no distinct rhizines or tomenta observed, and the hypothallus can be dark brown to black and protruding or not.