First mentioned in botanical literature by the Italian botanist Fabio Colonna in 1606, the species was formally described by Carl Linnaeus in 1753, who highlighted its unique physical characteristics such as its grey colour, its unusual leafy form with linear fringe-like segments, and the presence of hair-like structures (cilia).

Anaptychia ciliaris is readily recognizable by its fruticose (bushy) thallus that varies in colour from greyish-white to brownish-grey, to greenish when wet, and its large and distinctive cilia.

The internal anatomy of A. ciliaris makes it sensitive to air pollutants, leading to observable changes in its form when exposed to these conditions.

According to Annie Lorrain Smith, Anaptypia ciliaris was first mentioned in the botanical literature in 1606 by the Italian botanist Fabio Colonna in his Ekphrasis, a work known for its detailed illustrations of plants using copperplate engravings.

Linnaeus described it as a somewhat erect, leafy, grey lichen with linear, fringe-like segments that are ciliate (having hair-like structures, or cilia).

Linnaeus cited multiple references that described the lichen similarly, emphasizing its larger size, hairy characteristics, and shielded appearance.

Its fronds, akin to lobes of foliose lichens, lie close to the substrate with distinct upper and lower structures in a dorsiventral organization.

These colonies comprise neighbouring individuals each with elongated, linear structures (laciniae) that repeatedly branch dichotomously (into roughly equal parts).

Upon contact with nearby surfaces, often another lobe of its own thallus, these hapters induce branching and create a spreading sheath, leading to entanglement.

The lower surface features irregular veining and is adorned with rhizines (root-like attachment structures) along the margins, which are the same colour as the thallus.

The photobiont layer, housing cells measuring 10–15 μm in diameter, is frequently interrupted by the upper cortex, resulting in a discontinuous pattern.

[38] Widely distributed in Finland, it is abundant in populated areas, present in parks, alleys, and field edges, and also occurs on seashore cliffs.

Less commonly, it is found on Pinus sylvestris, P. nigra, Juniperus oxycedrus,[39] Acer pseudoplatanus (sycamore) and Fagus sylvatica (beech).

[40] Once common sight in Upper Austria, its decline is due to less availability of preferred substrate like mature, moss-covered, fertilised and dust-impregnated barks.

However, healthy specimens were unexpectedly found in 2010 on young ash trees in Brabant, a resurgence attributed to reduced air pollution and climate warming.

[51] Following the Chernobyl disaster, it played a significant role in the biomonitoring of airborne radioactive fallout, with detected caesium-137 activity in Anaptychia ciliaris reaching as high as 14560 becquerels per kilogram.

It was a blend of oakmoss, Anaptychia ciliaris, and species of Usnea, fragranced with ambergris or musk, combined with the essences of roses, jasmine, or orange blossoms.

[53] In the Ar Kaweit region of eastern Sudan, the lichen, known locally as bakour, was mixed with other plants and burned to repel insects.

Early on, the French botanist Joseph Pitton de Tournefort reportedly first observed the lichen's distinctive large, dark-coloured spores.

[23] In 1853,[58] Julius Ferdinand Speerschneider, another German botanist, reported the division of the lichen's photobiont cells (then referred to as gonidia) in moist thallus sections.

In his 1784 work Fundamentum Historiae Naturalis Muscorum Frondosorum, he described and depicted Anaptypia ciliaris apothecia, dark septate spores, and pycnidia.

In 1825, Joseph Placide Alexandre Léorier [fr] documented Roy of Tonnerre's pioneering technique to produce alcohol from lichens, notably Anaptypia ciliaris.

This innovation was remarkable because lichens, unlike fruits or grains, generally lack the abundant sugars usually used as feedstock in traditional alcohol production.

Its extracts, tested for antibacterial and insecticidal effects against certain pathogenic bacteria and the Culiseta longiareolata mosquito larvae, showed moderate larvicidal properties.

[66] In tests against fish bacterial pathogens, A. ciliaris demonstrated antibacterial effects, particularly towards Aeromonas hydrophila, Streptococcus agalactiae, Enterococcus faecalis, and Lactococcus garvieae.

In these settings, researchers grow the fungal component separately from its algal partner, allowing for a detailed examination of the fungus's individual characteristics and behavior.

These findings align with the lichen's characteristic slow growth rate and its ability to support apothecia of different ages on a single thallus, further contributing to genetic variation.

[72] Anaptychia ciliaris is part of a web of ecological relationships, serving as a host for various lichenicolous organisms, which are species that live on, and often parasitize, lichens.

This fungus produces spherical or tuberculate fruit bodies, ranging in colour from cream to pinkish, brownish, or blackish, and is found in Italy, Macedonia, Spain (including the Canary Islands), Sweden,[33] and Greece.

[74][75] In the UK, the Anaptychia ciliaris subspecies mamillata often shows tiny black dots on its lobes, a result of Stigmidium hageniae parasitism.