Usnea, also known as beard lichens, are a group of pale, grayish-green lichens that like to grow on anything from bark and twigs to tombstones and skulls. By the late Middle Ages, the latter was considered worth its weight in gold, as physicians prescribed cranial lichens for various ailments, and the nature of the death of the skull’s owner was believed to dictate the potency of the ‘medicine’.
Usnea, “the wig of a dead skull”, or muscus ex craneo humano (real moss from a dead man’s skull)
If a human head ends up abandoned in a cool, damp environment, such as in the UK, it decays and the resulting bony skull can become an anchor for Usnea. While the battles yielded a lot of head-losses to grow cranial lichens, the ingredient was so coveted that people cultivated it.
Exactly when cranial lichens began to be used as medicine is something difficult to pin down, wrote Christopher J Duffin in his article “The Wig of a Dead Skull”: Medicinal Cranial Moss. Written records date back to 1493, as detailed by Swiss physician Philippus Aureolus Theophrastus Bombastus von Hohenheim, but it is likely that it emerged as traditional medicine earlier than that.
In 1590, the “father of German botany” Tabernaemontanus (also called Jacobus Theodorus or Jacob Diether) published a volume of 2,255 plant illustrations titled Eicones plantarum seu stirpium. It contains a famous image of skull lichens growing on human remains and details how doctors and apothecaries would deliberately leave skulls in damp places where they would be colonized by woodland mosses. Usnea “clings” and “crawls back and forth like a long rough worm” on the surface of the skull, he wrote.
As for how they got those heads? Well, that’s a whole different Pandora’s box.
How Death and Head Delivery Impacted Usnea’s Value
When cranial lichens were a popular product on the drugstore shelf, it was widely believed that within the human body existed a soul or spirit. When a person died naturally, that soul was thought to be extinguished, but people who died by the sword or other violent means were considered full of beneficent spirit.
That our bones did not rot like flesh told the doctors of the time that they were the reservoir of this vital force and that it could be harvested to prolong the life of the living. The head was of particular interest, especially in cases where someone died by strangulation or hanging, as it was believed that this essentially squeezed the life force into the head. The bones of the skull would also have benefited from the glue of our brain.
“Belgian chemist Jean Baptiste Van Helmont…explained that after death the whole brain is consumed and dissolved in the skull”. It is, he believed, by ‘the continual absorption of [this] precious liquor” from dissolved brains, that “the skull acquires such virtues”, wrote Dr Richard Sugg In Mummies, Cannibals, and Vampires: The History of Corpse Medicine from the Middle Ages to Falun Gong.
“The skull here appears to have been almost marinated in its own brain. Steeped in the ‘precious liquor’ which refines and improves over time like a rare old wine, the brain-soaked skull acts as a sort of natural laboratory or alchemist vessel Try pairing it with artisan cheeses.
But a violent death and a marinade of brain mash weren’t the only things that dictated a skull’s value to usnea culture. At least not for the British.
“Despite [usnea’s] wide availability, there was only one type of skull that English physicians considered suitable: Irish,” wrote James Watson and William Regan in their paper Usnea and the Commodification of Irish Bodies in 16th and 17th Century London .
“After stories of large-scale massacres and beheadings by both sides in the conflict were passed on to the London public, English doctors and pharmacists came to regard the land across the Irish Sea as as a profitable reservoir of bodily medicine. As Francis Bacon wrote, the wars had left “heaps of slain bodies” unburied and ripe for the harvest.
Butchers and Bandits were enticed to fetch heads for both show and medicine at 16e century, and the delivery of a skull dictated its value. While a good “hedd monie” was paid for public figures (the Earl of Desmond’s head fetched £93 for a butcher named Kelly in the 1600s), it seems a supplement was given for style ( Captain Thomas Cheston won £120 for a skull around the same time as Kelly, simply for putting it back on the tip of his sword).
How was cranial lichen usnea used and consumed?
Skulls in lichen-adorned display cases were seen as a symbol of wealth and status in late medieval London. Consumers would take these skulls and scrape them for their lichens which were ground up and used to promote wound healing, treat whooping cough and manage epilepsy, among other things.
Van Helmont, in addition to promoting the benefits of brain slimes, had a story of a nobleman who had a wisp of skull lichen sewn inside his skin, Sugg wrote. You might gasp, but according to Van Helmont, the seemingly brutal act would save the nobleman’s life when, during a duel, he was struck in the head with a sword which, despite cutting his hat and his hair, failed to break his skin. .
And it gets even weirder. Cranial lichens were also the main ingredient of Unguentum armariun, or weapon salve, a liniment used in the “magnetic healing of wounds”. The practice was to heal wounds by applying a treatment to the weapon that inflicted it, rather than the wounds themselves.
“The weapon could be located very far from the injured person, and sometimes it could even be different from the one that had caused the injury, as long as it was of a similar shape; it could even be a stone, a stick or a dagger,” writes Paolo Modenesi in their journal Skull Lichens: A Curious Chapter in the History of Herbal Medicine.
“The weapon first had to be put into the wound, in order to open it and also to stain the weapon with blood. The weapon, or its dummy, was then anointed and bandaged until the wound The balm for weapons was renowned and very popular even in intellectual circles, and commonly used by doctors, convinced of its effectiveness.
So the next time you walk around and see a band of Usnea growing on a damp branch, take your hat off to its intricate history. In our time, humans have done some pretty weird things with the humble lichen and our own brain-gorged skulls.