In many of the old stories and tales of the island, it refers to "Llavor de Falguera" which is the seed of this plant as something very hard to find.
And so in some legends it is said that this seed has to be collected on a particular night of the year, June 24th, the night of Sant Joan, the Summer solstice or wearing special clothing.
It is said also that those are used to make magical ointments and balms, extraordinary potions that provide whoever drinks an enormous force, the abbility of seeing without being seen or even to be entitled to get a couple of little demons working for the protagonist of the tale in the pursuit of his also fantastic targets.
Could it be that all that was true if someone were able to find the precious seed of this plant. But being Pteridium Aquilinum that reproduces by spores and does not produce any seeds all that remain in the imagination like in a book writen by Gabriel Garcia Marquez.