[3] The species epithet torrefacta comes from the Latin word meaning "roasted", which aptly describes the lichen's dark brown, glazed upper surface.

The genus name Umbilicaria was introduced by Georg Franz Hoffmann, and it includes mostly rock-dwelling species primarily found in boreal, alpine, and Arctic regions worldwide.

He observed that it consists of one or several leaves of a somber black, brown, or dull hue, connected at the base by a central point or umbilicus.

He noted the upper side to be wrinkled with lobed and uneven margins, and a higher concentration of thin, compressed fibres and granulation towards the centre.

He also described the fruiting bodies as numerous, wrinkled, black sessile tubercles that seem to be composed of curled hairs, resembling those of Umbilicaria cylindrica, though less regular and less shiny.

Lightfoot remarked that this lichen was represented in one of the well-known images of cryptogams depicted by Johann Jacob Dillenius in his 1741 work Historia muscorum.

U. torrefacta is part of the subgenus Gyrophora, which is characterised by its rigid, non-pustulate thalli and specific chemical compounds, including gyrophoric and lecanoric acids.

The species in subgenus Gyrophora typically have smooth or granular upper surfaces and lack the pustulate structures seen in some other members of the family.

[14] The lower surface varies from pale brown to black and features irregular, thin, somewhat flattened layers resembling plates (trabeculae) that are often torn or perforated.

The ascospores (spores produced in the fruiting bodies) are colourless, hyaline (translucent), ellipsoid in shape, and not divided by septa (internal partitions).

The cells within these medullae are even more densely packed than in the "Deusta" type, resulting in narrow protoplasts that are challenging to observe under normal light microscope magnifications.

[13] The underside of Umbilicaria angulata also features plates positioned close to the umbilicus, but his species typically has branched, cylindrical rhizines.

Additionally, the lower surface of U. semitensis can vary from dark brown to black with distinct rhizines, sometimes giving it a similar appearance to U. torrefacta.

Additionally, U. nodulospora is primarily found on basalt in central Oregon to northeastern California, preferring steep, north-facing slopes.

[20] Umbilicaria torrefacta is commonly found in rocky, alpine environments within the Holarctic region, covering both the Palearctic and Nearctic biogeographical areas.

It is occasionally exposed to sea spray, although it tends to favour more sheltered, less frequently wetted environments compared to its relative Umbilicaria deusta.

Reflectance spectra for U. torrefacta range from 3% to 7% in the visible spectrum, which is relatively low due to the presence of chlorophyll and other pigments that absorb light.

This lichen species, like many others, shows specific absorption features near 685 nanometres (nm) associated with chlorophyll, making it identifiable through hyperspectral imaging.

[22] Umbilicaria torrefacta has a pattern of growth characterised by rapid initial expansion followed by a gradual slowdown as it approaches its maximum size.

A study conducted over a 240-year chronosequence in the foreland of the Hellstugubreen glacier in Jotunheimen National Park, Norway, found that the initial growth rate of U. torrefacta is relatively slow compared to other Umbilicaria species, averaging 0.9 mm per year.

This skewed size distribution indicates ongoing recruitment and colonisation in newly exposed areas, typical of primary succession in alpine environments.

Despite this, the species demonstrates resilience and the ability to establish itself successfully in newly available habitats, contributing to the stability and persistence of alpine lichen communities over time.

The combination of slow growth, delayed reproduction, and continuous recruitment enables it to maintain a stable presence in dynamic and often harsh habitats, playing a role in the ecological succession following glacier retreat and other disturbances in high-altitude regions.

These structural variations allow the lichen to maintain a stable symbiotic relationship between the fungal and algal components, which is crucial for its survival.

The thallus structure of U. torrefacta shows a significant degree of plasticity, allowing it to grow in environments with fluctuating humidity and light levels.

The lichen has a capacity to maintain a stable pigment composition, including chlorophylls and carotenoids, under conditions of different environmental stresses.

These pigments play a crucial role in photosynthesis and protection against UV radiation, helping to ensure the lichen's survival in the exposed, often extreme conditions of its habitat.

The fermentation method involves soaking the lichen in an ammonia solution for several weeks to produce rich red and purple dyes.