Madder root

Rubia
Rubia tinctorum
Scientific classification
Kingdom:	Plantae
Clade:	Angiosperms
Clade:	Eudicots
Clade:	Asterids
Order:	Gentianales
Family:	Rubiaceae
Subfamily:	Rubioideae
Tribe:	Rubieae
Genus:	Rubia L.
Type species
Rubia tinctorum L.

Rubia is a genus of flowering plants in the Rubiaceae family. It contains around 80 species of perennial scrambling or climbing herbs and subshrubs native to the Old World. The genus and its best-known species are commonly known as madder, e.g. Rubia tinctorum (common madder), Rubia peregrina (wild madder), and Rubia cordifolia (Indian madder).

Rubia was an economically important source of a red pigment in many regions of Asia, Europe and Africa. The genus name Rubia derives from the Latin meaning "red".

The plant's roots contain an anthracene compound called alizarin that gives its red colour to a textile dye known as Rose madder. It was also used as a colourant, especially for paint, that is referred to as Madder lake. The synthesis of alizarin greatly reduced demand for the natural compound.

Several species, such as Rubia tinctorum in Europe, Rubia cordifolia in India, and Rubia argyi in east Asia, were extensively cultivated from antiquity until the mid nineteenth century for red dye, commonly called madder. Cloth dyed with it has been found on Egyptian mummies. It was the ereuthedanon (ἐρευθέδανον) used for dyeing the cloaks of the Libyan women in the days of Herodotus. It is the erythrodanon (ἐρυθρόδανον) of Pedanius Dioscorides, who wrote of its cultivation in Caria, and of Hippocrates, and the Rubia of Pliny.R. tinctorum was extensively cultivated in south Europe, France, where it is called garance, and the Netherlands, and to a small extent in the United States. Large quantities were imported into England from Smyrna, Trieste, Livorno, etc. The cultivation, however, decreased after alizarin was made artificially.

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Wikipedia