Isatis tinctoria

It was formerly cultivated in large areas of Europe, from Middle East to Afghanistan and N India, Central Asia, Egypt, China, seldom in South America. During the Middle Ages and at the beginning of the Modern Age centres of cultivation were located in S England, S and NW France, Italy (Tuscany) and Germany (Thuringia as well as the lower Rhine area). At that time this species had an international economic importance as a dye plant, the blue dye could be produced from the leaves; it could also be used as an ingredient for certain other colours. Therefore, it was considered in former times as an universal vegetable dye plant. Its cultivation is known from the ancient time, because the Celtic and Teutonic tribes used this species already. After importing the proper indigo (see Indigofera spp.) the cultivation decreased rapidly in the 17th cent. But during the continental embargo of Napoleon I its acreage increased for a short time. The cultivation disappeared completely during the late 19th cent. (also last cultivation in Germany in Thuringia). Large- and glabrous-leaved forms were mainly cultivated. Formerly this plant was also used for medicinal purposes, recently it is propagated in Russia as a forage plant. As a dye plant it is today still cultivated in gardens in central Asia, mainly for preparing home-made cosmetics. Recently cultivation has come into a period of revival in several European countries. From the systematic point of view this species belongs to a very variable group, in which continous variation makes the species delimitation very difficult. It is also not clear whether some of the synonyms represent true species (i.e. I. indigotica) or whether further taxa need to be taken into account. This complex has its centre of diversity from the Middle East to Transcaucasia.