It houses a green algal photobiont, possibly the algae Myrmecia, which collaborates with the fungus to perform photosynthesis.

Within these structures, the supporting filaments, or paraphyses, may be simple or branch towards their tips, which do not expand or form a cap, staining a dusky blue when iodine is applied.

The spore-producing asci are elongated, either club-shaped or cylindrical, featuring a distinctive structure at their tips where a central tube stains blue with iodine within a lighter-staining area, surrounded by a clear amyloid ring.

For asexual reproduction, Psoroma develops pycnidia, which are pale brown, and produces simple, rod-shaped, colourless conidia.

[9] Chemically, Psoroma usually lacks detectable secondary metabolites (lichen products) through thin-layer chromatography, although in rare cases, porphyrilic acid and related compounds may be present.