First described by Thomas Taylor in 1836, it is one of the most prevalent lichen species globally, known for its resilience to pollution and cosmopolitan distribution across temperate and cold regions of both hemispheres.

[3] In 1962, Mason Hale and Syo Kurokawa designated a specimen from Lough Bray, County Kerry, as the lectotype for Parmelia sulcata.

[4] Molecular phylogenetics studies revealed significant genetic variability within Parmelia sulcata, indicating that it is a complex of cryptic species.

P. encryptata was described as morphologically similar to P. sulcata but genetically distinct, with a unique insertion in the internal transcribed spacer region and specific nucleotide differences.

[11] Parmelia sulcata is a foliose lichen with a generally circular thallus that can range in color from glaucous white to gray on the upper cortex; the lower surface is black.

[15] In terms of standard spot tests, the upper surface of Parmelia sulcata reacts K+ (yellow), KC−, C−, and P−, indicating the presence of the secondary metabolites (lichen products) atranorin and chloroatranorin.

Parmelia sulcata reproduces vegetatively through soredia, which contain both fungal and algal cells, potentially influencing the selection of compatible photobionts.

Overall, the study suggests that the biodiversity patterns of photobionts in Parmelia are influenced by a combination of ecological, climatic, and evolutionary factors.

Identifying Parmelia sulcata and its similar species based solely on morphology and chemistry can be challenging due to overlapping characteristics and intraspecific variability.

Understanding these differences enables researchers and lichenologists to better identify and study Parmelia sulcata and its closely related species, contributing to more accurate distribution records and ecological knowledge.

[14] Parmelia asiatica is distinguished by its predominantly circular and semicircular, terminal, or marginal soralia, and narrow sublinear lobes.

Both species have salazinic acid in the medulla, but the unique characteristics of P. asiatica's soralia and lobes provide a visual distinction.

[14] In Africa, Parmelia sulcata has been documented from the low alpine zone in Ethiopia and Kenya, at elevations ranging from 3,500 to 4,200 m (11,500 to 13,800 ft), but it is otherwise rare.

The species composition of lichens, including Parmelia sulcata, changes from the base to the crown of the trees, indicating the importance of light conditions in their distribution.

[24] A study conducted in a temperate deciduous forest of Central Italy monitored carbon dioxide (CO2) gas exchange, radial growth, chlorophyll content, and photobiont density of Parmelia sulcata over a year.

The results showed significant seasonal variations, with CO2 gas exchange and radial growth peaking in December, and photoinhibition occurring in early spring before tree leaves sprouted.

These findings suggest that the seasonal acclimation of lichen photosynthesis and chlorophyll content is influenced by variations in photobiont population density, potentially related to changes in nutrient availability.

[26] Another fungus that appears to be obligately parasitic on P. sulcata, Perigrapha superveniens, causes the formation of irregularly shaped to undulate (wavy edged) galls, and prefers its host to live in oceanic areas.

Later methods solved this by first boiling the crotal alone to extract the colour, then adding the wool at a lower temperature to prevent tangling and damage.

As a species sensitive to air quality changes, its presence or absence can indicate pollution levels, particularly in industrial areas, urban settings, and natural habitats.

It has been observed to reappear in areas where sulfur dioxide levels have decreased, making it a useful bioindicator of improving air conditions.

Studies have used it to monitor heavy metals in industrial areas and persistent polycyclic aromatic hydrocarbon pollution in the Pyrenees.