531. Rubia.—Madder.
Botanical name:
531. RUBIA.—MADDER. The rhizome of Rubia tinc'torum Linné. Habitat: Levant and Southern Europe, chiefly supplied from Holland, where it is cultivated. Usually comes into market in a coarse, red powder. Its most important constituent is alizarin, a red coloring-matter soluble in water and alcohol. Chiefly used as a dye.