[5] It forms thin to moderately thick patches on tree bark, appearing yellowish-white to greenish-grey in colour, and features vivid red to deep reddish-orange spore-producing structures (apothecia).

Since its description by the Scottish botanist James Stirton in 1881, it has been found across the Southeastern United States, Central and South America, parts of Africa, India, Sri Lanka, China, and northeastern Australia, where it plays a role in forest ecosystems by contributing to nutrient cycling and providing microhabitats for small invertebrates.

[7] The crustose thallus of Haematomma accolens ranges from thin to moderately thick, with a texture varying from smooth to slightly roughened or cracked.

[8] Haematomma accolens contains atranorin and placodiolic acid in its thallus, while the apothecia contain the anthraquinone pigment haematommone, which is responsible for their vibrant red colouration.

The combination of placodiolic acid in the thallus and haematommone in the apothecia helps distinguish H. accolens from chemically similar species such as Haematomma flexuosum.

[8] Morphologically, both species share a crustose thallus and vivid reddish apothecia, but H. accolens is typically characterised by smoother apothecial margins that lack the irregular flexuous shape sometimes seen in H. flexuosum.

For example, H. persoonii has smaller, less septate spores and often crowded apothecia, while H. ochroleucum is distinguished by the presence of porphyrilic acid and a different range of thallus colours.

[10] Ecologically, H. accolens is part of lichen communities on tree bark, where it contributes to nutrient cycling and provides microhabitats for small invertebrates.