Woad

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iWoad

Woad flowers

Scientific classification

Kingdom:	Plantae
Division:	Magnoliophyta
Class:	Magnoliopsida
Order:	Brassicales
Family:	Brassicaceae
Genus:	Isatis
Species:	I. tinctoria

Binomial name

Isatis tinctoria
L.

Woad (or glastum) is the common name of the flowering plant Isatis tinctoria in the family Brassicaceae. It is occasionally known as Asp of Jerusalem. Woad is also the name of a blue dye produced from the plant. Woad is pronounced to rhyme with road (IPA pronunciation: [woʊd]).

Woad is native to the steppe and desert zones of the Caucasus, Central Asia to eastern Siberia and Western Asia (Hegi), but is now found in southeastern and some parts of Central Europe as well. It has been cultivated throughout Europe, especially in Western and southern Europe since ancient times.

1 History of woad cultivation
2 Woad and indigo
3 Woad and health
4 Ethnomedical Use
5 External links and references

[edit] History of woad cultivation

Until the end of the 16th century, when indigo became available as trade routes from the far east developed, woad was the only source for blue dye available in Europe.

The first archaeological finds of woad seeds date to the Neolithic and have been found in the French cave of l'Audoste, Bouches du Rhone (France). In the Iron Age settlement of the Heuneburg, Germany, impressions of the seeds have been found on pottery. The Hallstatt burials of Hochdorf and Hohmichele contained textiles dyed with woad. Julius Caesar tells us (de Bello Gallico) that the Britanni used to dye their bodies with woad (vitrum), which made them look terrifying in battle. The Picts may have gotten their name (Latin Picti which means painted folk or possibly tattooed folk) from their practice of going into battle naked except for decorations made with woad war paint. (This has been commemorated in the humorous (modern) British song The Woad Ode.)

In addition to its use as a tattooing ink, it is believed that woad was used as an astringent. It produces quite a bit of scar tissue, but heals very quickly, and no blue is left behind. It may have been used specifically for closing battle wounds.

In Viking age levels at York, a dye shop with remains of both woad and madder dating from the 10th century have been excavated. In Medieval times, centres of woad–cultivation lay in Lincolnshire and Somerset in England, Gascogne, Normandy, the Somme, Toulouse and Britanny in France, Jülich, the Erfurt area in Thuringia in Germany and Piedmont and Tuscany in Italy. The citizens of the five Thuringian woad-towns of Erfurt, Gotha, Tennstedt, Arnstadt and Langensalza had their own charters. In Erfurt, the woad-traders gave the funds to found University Erfurt. Traditional fabric is still printed with woad in Thuringia, Saxony and Lusatia today: it is known as Blaudruck (literally, 'blue dyeing').

Medieval uses of the dye were not limited to textiles. For example, the illustrator of the Lindisfarne Gospels used a woad-based pigment for blue paint.

[edit] Woad and indigo

Woad plants in their first year

The blue pigment in woad is the same as in indigo dye, but the concentration of the pigment is greater in indigo. With the European discovery of the seaway to India, great amounts of Indigo were imported. Laws were passed in some parts of Europe to protect the woad industry from the competition of the indigo trade. Indigo was proclaimed to rot the yarns as well. "In 1577 the German government officially prohibited the use of indigo, denouncing it as that pernicious, deceitful and corrosive substance, the Devil's dye." (Lippincott's Magazine of Popular Literature and Science, Volume 17, No. 100, April, 1876.) [1] "... a recess of the Diet held in 1577 prohibited the use of 'the newly-invented, deceitful, eating and corrosive dye called the devil's dye.' This prohibition was repeated in 1594 and again in 1603 (D G Schreber, Historische, physische und economische Beschreibung des Waidtes, 1752, the appendix)." (Thorpe JF and Ingold CK, 1923, Synthetic colouring matters - vat colours. London: Longmans, Green and Co., p. 23). With the development of a chemical process to synthesize the pigment, both the woad and natural indigo industries collapsed in the first years of the twentieth century. The last commercial harvest of woad until recent times occurred in 1932, in Lincolnshire, Britain.

In Germany, there are attempts to use woad to protect wood against decay without dangerous chemicals. Production is also increasing again in the UK for use in inks, particularly for inkjet printers, and dyes, as woad is biodegradable and safe in the environment, unlike many synthetic inks. Isatis tinctoria is viewed as an invasive species in parts of the United States.

[edit] Woad and health

Recently, scientists have discovered woad might be used to prevent cancer, having more than 20 times the amount of glucobrassicin contained in broccoli.[2] Young leaves when damaged can produce more glucobrassicin, up to 65 times as much. [3]