Isatis tinctoria

Isatis tinctoria, or woad, is a flowering plant in the mustard family cultivated historically in Europe and western Asia for blue dye.

Woad dye: A blue dye made from leaves of Isatis tinctoria through fermentation and oxidation. The plant’s best-known product came from processing its leaves into indigo-bearing dye.
Indican: A colorless indoxyl glucoside found in woad and some other plants. Woad leaves store a precursor that processing can convert into indigo.
Iron Age Europe: The period and societies of Europe characterized by widespread use of iron tools and weapons. Archaeological evidence associates woad use with ancient European textile practices.
Brassicaceae: A flowering-plant family that includes mustards, cabbages, and many other species. Woad belongs to this family, whose flowers typically have four petals.
Indigo dye: A blue dye whose color comes from insoluble indigo pigments applied to fibers by reduction and oxidation. Woad supplies indigo, the pigment responsible for its characteristic blue.
Indoxyl: A reactive chemical compound that oxidizes and couples to form indigo. It is the intermediate linking woad’s leaf chemistry to blue pigment formation.
Celtic culture: The diverse languages, societies, and material traditions of ancient and modern Celtic peoples. Ancient accounts linked blue body coloring with peoples described as Britons or Celts.
Flowering plant: A plant that produces flowers and encloses its seeds within fruits. Woad’s flowers and seed-bearing fruits identify it as an angiosperm.
Woad balls: Compressed balls of crushed woad leaves, dried for storage and later dye processing. This traditional form made harvested leaves transportable and storable.
Fermentation: Chemical transformation by microorganisms or enzymes, often occurring without oxygen. Traditional woad processing used fermentation to release dye-forming compounds from leaves.

Linked from 4 pages