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"[Plin. Nat. 27.48.] - THE DRYOPTERIS: TWO REMEDIES.
The dryopteris, which resembles fern in appearance, is found growing upon trees; the leaves are of a somewhat sweetish flavour and marked with slight indentations, and the root is hairy. This plant is possessed of caustic properties, and hence the root is pounded and used as a depilatory. In using it the skin is rubbed with it till perspiration is excited, the operation being repeated a second and a third time, care being taken not to remove the perspiration. "
(The Natural History. Pliny the Elder. John Bostock, M.D., F.R.S. H.T. Riley, Esq., B.A. London. Taylor and Francis, Red Lion Court, Fleet Street. 1855.)