[5] The thallus of Chaenotheca brunneola is immersed in its substrate, whereas the extends to 1.5 mm, upon which rests a shiny black spherical mazaedium.

[6] In a 2016 study, the authors show that Chaenotheca brunneola appears to comprise multiple distinct species that are morphologically similar but genetically different.

This suggests there are cryptic species within what has been considered C. brunneola, with substrate specificity (wood vs. fungal fruit bodies) corresponding to distinct genetic lineages.

The authors consider this a case of convergent evolution leading to morphologically similar but genetically distinct species adapted to different substrates.

[7] The lichen typically grows on wood, particularly on snags (standing dead trees) of pine (Pinus sylvestris), spruce (Picea abies), and birch.