Polytrichum juniperum - Hair-cap moss
"CONSTITUENTS: -
PREPARATIONS: Specific Polytrichum. Dose: from five to sixty minims.
Therapy: The agent is a hydragogue diuretic and causes a very large evacuation of urine when administered in dropsy, while it promotes the absorption of the fluid at the same time. It tends to relieve the pain of urinary calculi and to prevent their formation.
Though it is not always effective, probably on account of using a spurious article, the genuine has been known to remove forty pounds of urine from a dropsical patient in twenty-four hours."
(Finley Ellingwood: The American Materia Medica, Therapeutics and Pharmacognosy, 1915)