Rubia

Rubia is a genus of flowering plants in the Rubiaceae family, commonly known as madder. The genus comprises several species of climbing or ground‑covering perennial herbs native to the Old World, especially Europe, western Asia, and Africa, with some species cultivated or naturalized elsewhere. Rubia species typically have slender rhizomes and small flowers, often pink or white, followed by red to black fruits.

The most economically important species is Rubia tinctorum, the dyer's madder, whose roots contain red pigments including alizarin and purpurin. Ground and processed roots yield red dyes that were used for textiles for centuries, with a long‑standing role in European and Mediterranean dyeing. The dye is typically used with mordants to produce madder lake pigments for paint and printing.

In the 19th century, the isolation and commercial production of synthetic alizarin reduced demand for natural madder, leading to a decline in traditional cultivation in many regions. Today, madder cultivation persists on a smaller scale for traditional textile work and niche dye applications. Other species such as Rubia peregrina (wild madder) and Rubia cordifolia (Indian madder) have also been used to dye fabrics and in traditional crafts, and they appear in regional herbal and ethnobotanical sources.

Rubia is a member of the Rubiaceae family, which includes coffee and gardenia. The genus is of interest for its historic role as a natural dye source and for contemporary interest in natural pigments and sustainable dyeing practices.