Natural materials, including many plants, were the source of all dyes until the late nineteenth century. Blue dye was historically rare and was obtained from the indigo plant (Indigofera tinctoria). Another color difficult to obtain for dye was red; the madder plant (Rubia tinctorum) was an excellent source of red dye and was used for the famous “red coats” of the British Army. Other, more common, natural dyes derived from plant sources are summarized in the following chart: