Tibell is a dense gray crust covered in raised warts, featuring dark grain-like structures called soredioid isidia.

Certain robust specimens of Cyphelium, with apothecia either sessile or partially immersed, closely resemble Thelomma (like T. ocellatum and T. occidentale (Herre) Tibell).

Nevertheless, occurrences west of the Cascade crest in Oregon and Washington are sparse, and the species is notably absent from extremely coastal areas.

[5] Thelomma ocellatum exhibits a high specificity in its habitat requirements, typically colonizing bare wood surfaces.

[2] Dispersal of Thelomma ocellatum primarily occurs through vegetative means, with both spores and diaspores likely disseminated by birds frequenting the substrates it inhabits.

Unlike many ascomycetes, Thelomma and other mazaedium-producing species accumulate spores that are dispersed by external agents rather than being forcefully ejected.