For an interesting discussion of the many uses of Althaea officinalis, besides being the source for the orignal "marshmallow," look here.  The Egyptians used the roots of the plant for making a marshmallow-type confection, and although there are many other uses, medicinal and culinary, I grow it just because I think it's pretty to look at.  This long-lived perennial, with soft green, downy leaves and white/palest of pink blooms, grows from four to six feet in sun/part shade.  Zones 3-9.  Quarts.  (Illustration by Hermann Adolf Kohler (1834-1879) from Kohler's Medizinal Pflanzan, from Wiki Commons.)