They have a complex internal structure, including large crystal clusters embedded within the photobiont layer, which may be an adaptation for light management in their typically shaded habitats.

[2] In a later analysis, it was shown by part of a lineage with both rock-dwelling and bark-dwelling Porina species having crustose and non-lobate thalli; as Damien Ertz and Paul Diederich suggest, "this raises some doubts about the use of the ascospores and thallus type alone for defining genera in the Porinaceae.

The thallus surface appears smooth but features a unique network of reticulate (net-like) or meandering lines, which are most visible when the lichen is wet.

[2] Saxiloba firmula, the type species, is found in the Caribbean, including Cuba, Isla de la Juventud (formerly Isle of Pines), Puerto Rico, and the Bahamas.

It primarily grows on calcareous rocks in dry forests of western and central Cuba, typically inhabiting shaded microhabitats, although it can tolerate some sun exposure.

[4] The vertical arrangement of crystal clusters and algal cells within the thallus of Saxiloba species has been interpreted as an adaptation to manage light in their respective habitats.

This structure could help distribute light more evenly through a thicker photobiont layer, potentially allowing the lichens to accumulate more biomass in low-light conditions.