Osmunda regalis - Buck thorn brake, Royal flowering fern
"CONSTITUENTS: -
PREPARATIONS: An infusion of the roots is given and taken quite freely. A tincture may be obtained. The substance is very mucilaginous, and an infusion will quickly become jelly-like.
Therapy: With some physicians this agent is very popular in the treatment of the above disorders. It is also useful in weak back, especially in those cases where, with weakness of the muscular structure of the back, there are symptoms of incipient disease of the spinal vertebrae. It has been used also in subluxations.
In the treatment of diarrhea and dysentery, whether acute or accompanying protracted fevers, the agent is said to be very beneficial, especially if accompanied with great weakness. Also as a tonic during convalescence, when these conditions have prevailed. It has been given in various form of female weakness, particularly where there was severe leucorrhea. Its soothing influence upon mucous surfaces seems to be remarkable."
(Finley Ellingwood: The American Materia Medica, Therapeutics and Pharmacognosy, 1915)