Althea officinalis.

Botanical name: 

ALTHEA OFFICINALIS, L. Marsh Mallow. European plant, becomes spontaneous with us in many places. Plant and root mucilaginous, demulcent, emollient; used in cataplasms, gargles, fomentations, clysters, and decoctions, for diseases of the throat and lungs, bowels, bladder, and urethra, also for pains, irritations, and inflammations. Equivalent to mallow and gum Arabic, but better. In France, lozenges of it are used for cough.

Medical Flora, or Manual of the Medical Botany of the United States of North America, Vol. 2, 1830, was written by C. S. Rafinesque.