The thousand uses of lichens

Throughout history, humans have used lichens for a variety of purposes. The oldest evidence of lichen use dates back to the ancient Egyptians, who used some species to make bread flour and others for cosmetic and medicinal purposes. They also used the Pseudovernia furfuracea species to mummify corpses. The famous Lecanora esculenta, found in abundance in the mountains of Asia Minor and used for food, is known as the 'manna lichen': when it dries out, this species forms pellets that break off from the ground and can be blown about by the wind. According to some scholars, it is the manna described in the Bible. Cetraria islandica (also known as Iceland lichen) is very popular, and was once even described as a 'god's gift to humans' because of its many uses for both food and medicine: its thalli are used in the preparation of decoctions, soups, throat lozenges, candies and flour, also used in the confectionery industry for dietary products. Used in the form of decoction and infusion, Iceland lichen also served as food during the famine in Norway between 1807 and 1914 and during World War II. From the 5th century onwards, many lichen species have been used in medicine. There was a widespread belief that plants had medicinal properties according to their characteristics and morphological similarities with certain human body parts. Thus, Lobaria pulmonaria (tree lungwort) was used to treat the bronchi and lungs simply because the veins on its surface resembled those of lungs;Usnea barbatawas used to treat baldness, because this lichen has a densely branched shape reminiscent of a thick hair. Xanthoria parietina, due to its yellow-orange colour, was used as a remedy for liver complaints. In the 16th and 17th century many physicians recommended using certain species of Usnea, Cladonia, Cetraria, Lobaria, Evernia and others for their expectorant, stimulant, tonic and antibiotic properties. Nowadays, medical interest is mainly linked to the antibiotic properties of certain substances produced by lichens. Lichens have also been known since Ancient Greek times as excellent dyes. Before the invention of synthetic dyes, they were of great economic importance for the dyeing of wool. The best known species is Roccella tinctoria, from which 'lacmus', used for litmus paper, and orcein, a red dye for wool, can be extracted. In Scotland,Ochrolechia tartarea was used on a large scale to dye fine woollen fabrics brown. Various species of lichen provided different pigments and by mixing different species new colours and shades could be obtained. Lichens are also used in the preparation of perfumes. The most widely used species are Pseudevernia furfuracea and Evernia prunastri, from which a substance called 'oakmoss' is made, providing the essence of 'Orient', 'Cyprus' and 'Russian Leather' fragrances.

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The thousand uses of lichens

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