Definition of "fern-seed" [fern-seed]

• The seed of a fern; collectively, the seed-like bodies constituting the spores of ferns: formerly supposed to possess wonderful virtues, such as the power of rendering a person carrying it invisible. (noun)

The Century Dictionary (Public Domain)

• "We will know what he really is — he shall not wear fern-seed, and walk among us invisible thus — what say you,"
• "Nay, by my faith, I think you are more beholding to the night than to fern-seed for your walking invisible."
• "We steal as in a castle, cocksure; we have the receipt of fern-seed, we walk invisible."