# Fern seed

*The “seed” of ferns*

**Known today as.** The spores of ferns, mistaken for seed.

Kind: Plant

## What was it used for?

None in medicine; a charm.

## What does modern science say?

Ferns reproduce by spores, not seeds, which is why the “seed” seemed invisible.

## Pharmacognosy and toxicology

- **spores**: the “seed”; ferns have none
- **filicin**: in the male fern rhizome, not the spore

**Mechanism.** There is no seed: ferns reproduce by spores, invisible to the eye on the frond’s underside, and the invisible seed that gave invisibility was an inference from a plant that seemed to seed unseen. The spores are inert.

**Dose.** None.

**Standing.** A charm; the fern that has a pharmacology is the male fern, whose rhizome was the taenicide of the pharmacopoeias until the 1950s.

## What lore surrounds it?

Gathered on St. John’s Eve, it was held to make its bearer invisible: “we have the receipt of fern-seed, we walk invisible.”

## What did the older authorities say?

**Pliny.** Pliny knows the polypody fern as “filicula,” which “bears some resemblance to fern.” Its fibrous root, “of a grass green colour within, about the thickness of the little finger, and covered with cavernous suckers like those on the arms of the polypus,” is steeped in water or sprinkled on cabbage, beet, mallows or salt meat, or boiled with pap “as a gentle aperient for the bowels.” Dried and powdered and applied to the nostrils “it cauterizes polypus of the nose.” And he records the point that later fern-seed lore turned to magic: “It has neither seed nor flower.”

## Sources

- Shakespeare, *Henry IV, Part 1* II.1.
- Pliny the Elder, *Natural History* 26.37, trans. J. Bostock & H. T. Riley (1855), Perseus Digital Library.
- Thiselton-Dyer, T. F. (1889). *The Folk-lore of Plants*, ch. 10.

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*Fern seed.* In *Materia Medica*, edited by B. C. P. Statema. Version 1, revised 2026-10-01. The Thinking Press. https://thethinkingpress.org/materia-medica/fern-seed

Historical description, not medical advice.