The only lichen employed medicinally by British practitioners is Iceland moss (Cetraria islandica). But several other lichens, whose medicinal qualities are in reality similar to, though much feebler than, Iceland moss are still kept in the London herb shops, being occasionally employed as popular remedies. Those which I have met with are Peltidea canina, Scyphophorus pyxidatus, and Sticta pulmonaria. These, as well as Gyrophora, Parmelia parietina, and Cladonia rangiferina, require a short notice.
The Elements of Materia Medica and Therapeutics, Vol. II, 3th American ed., was written by Jonathan Pereira in 1853.