[2] Bacidina species are crustose lichens, forming thin, often inconspicuous thalli that may be smooth, cracked, warted, or granular.

The photosynthetic partner (photobiont) consists of chlorococcoid algae, which have roughly spherical (globose) to broadly ellipsoidal cells.

They lack a distinct thalline margin but have a well-developed true exciple, which is composed largely of thick-walled cells with isodiametric to ellipsoidal lumina.

The ascospores are colourless, generally three- or more-septate at maturity, and often filiform (thread-like), acicular (needle-shaped), or sigmoid (curved like an "S"), though some species have spores that are cylindrical to fusiform.

Bacidina species do not contain secondary metabolites that react with common chemical spot tests (C–, K–, KC–, Pd–, I–, UV–), but their apothecia and pycnidia may contain a variety of pigments.