When I was in medical practice in Strasbourg in the late 1990s, my landlord, Philippe Stoll-Litschgy, an elderly Alsatian artist and restorer, would sometimes come down first thing in the morning from the top-floor studio workshop in the building he had inherited from his adoptive parents (I rented the ground floor) and pass through the surgery before patients turned up. He was there to water the bracken ferns growing in the small courtyard at the back of the surgery and which could be seen though the louvred window across from my desk. This was his fern nursery. I was fond of Monsieur Stoll, with his beehive haircut and his limp, which made him appear to be an even more theatrical personage than he actually was; and I liked him too for his appreciation of ferns – ‘Faut bien que je m’occupe de mes fougères!’ he would exclaim when I interrupted him during their tending. There was never any question of his not doing so; it was his apartment, after all.

I’ve always been a fern-fancier myself, owing to their antiquity and their simplicity, and the fact that their method of reproduction for so long remained a mystery: Linnaeus himself, in his Species plantarum, coined the term ‘cryptogamia’ to express what seemed to be the hiddenness of the sexual cycle of algae, lichens, mosses and ferns, as opposed to that of phanerogams – plants whose reproductive organs are readily visible as flowers.

It is all done by spores. While flowering plants rely on their ...