oak fern

English

Noun

oak fern (plural oak ferns)

1. Any of various ferns which grow on trees and walls, specifically common polypody, formerly thought to have medicinal properties when found growing on an oak.
   • 1603, John Florio, translating Michel de Montaigne, Essays, II.12:

     Why say we, that [...] to know the vertue of Reubarb, qualitie of Oak ferne, and operation of Polipodie, is only peculiar unto man?