MUSHROOMS — specifically magic ones — are in the spotlight. A growing body of research is showing that psilocybin, the main psychoactive compound in magic mushrooms, has potential in treating psychological disorders like depression, addiction and PTSD.

Of the nearly 200 species of psychedelic mushrooms that have been identified worldwide, mainly in Central America, only one — Psilocybe semilanceata — grows in any abundance in northern Europe. Like many mushrooms, Psilocybe semilanceata is generally known not by its scientific designation, but by its common or folk name, the “liberty cap” mushroom.

For years, this bothered me. As a Roman historian, I know the liberty cap — the pileus, in Latin — was a hat given to a Roman slave on the occasion of their being freed. It was a conical felt cap, shaped like that of a smurf and which undeniably bears a clear resemblance to Psilocybe semilanceata’s distinctive pointy cap.