His diagnosis of the genus was as follows (translated from Latin): "Apothecium wart-like, formed from the thallus, including several thalamia covered by a very delicate, transparent perithecium, marked above by impressed ostioles; nuclei somewhat globose, containing cellular vesicles.

[3] The genus Porina comprises crustose lichens, characterised by their crust-like appearance that can range from being completely immersed in their substrate to sitting on the surface.

Some species within this genus may develop isidia—small outgrowths that aid in vegetative reproduction—or, more rarely, soralia, which are structures that produce soredia for reproduction.

The photosynthetic partner, or photobiont, in Porina is typically green alga from the genus Trentepohlia.

[4] Porina lichens produce perithecioid ascomata, which are flask-shaped structures where spores develop.

The conidia (asexual spores) are usually aseptate (without internal partitions), ranging from cylindric-ellipsoidal to rod-shaped or, more rarely, filiform (thread-like).