Woad.

Am currently reading "Colour" by Victoria Finlay and find it wonderfully interesting. Woad is a plant that produces the colour Indigo, which the ancient Britons used to coat themselves with in times of battle as a symbol of fierceness. As Woad produces prolific amounts of seed which float easily on the wind, it grew everywhere and in time it's name morphed into "weed".
The name Indigo derives from the Greek meaning "from India" The true Indigo plant does come from India, but Woad which also produces the Indigo colour comes from Britain, although it's colour is not as pure.

She's wrong about the woad/weed connection.

I just looked in the dictionary and they translate "woad" as "guede", but I know it as "pastel". The culture of pastel here in southwestern France made the fortune of merchants in Toulouse before indigo was imported from India, killing the market.

There is a shop in the old centre of Toulouse selling stuff like this and with information about the plant.

Woad is Isatis tinctoria. In the US, it's known as Dyer's Woad. It is not native to the US and is considered a noxious weed.

Other species of Isatis+ have long been used in Chinese traditional medicine. +I. tinctoriia is known to have some antibacterial & antiviral properties. Chemicals in it may have some effect on stimulating the immune system. It is also being investigated for chemicals that may be useful in treating some cancers.

Vinny, I was quoting the words in the book -- "The seeds of this mustard plant Isatis tinctoria float so easily in the wind and settle in so many different soils that anything unwanted in gardens or fields became known as a "woad" and later, with a vowel change, as a "weed".
I tend to believe what I read, naive but true.
Nutrax, I read that Utah is still overrun by the descendants of woad seedlings planted by Mormon dyers in the nineteenth century. Thanks for the extra information re. herbal medicine.

Shona, when I said "she" I meant the author of the book.

I was taught at school that the ancient Britons, after covering their chests with woad, drew a licked forefinger down their sternum to remove a stripe of paint. This was the origin of the white line running down the centre of the woad.

She use to work at the South China Morning Post and had a truly obnoxious cut glass posh English accent. I'm not surprised she got it wrong. No personal animus there at all!

Dyers Woad is known locally in far northern California as "Marlahan Mustard." The name comes from a local family that got a shipment of hay contaminated with woad seed.

It was probably imported into the US in the 17th Century as a plant for dye. However, the real problems started in the late 19th C./early 20th C with shipments of contaminated alfalfa seed from Europe. The Utah problem had nothing to do with Mormon settlers.
>Alfalfa seed containing dyers woad seed was imported from Ireland to Siskiyou County, California, in the early 1900's. The contaminated seed was responsible for the introduction of Dyer's Woad into northern California and southern Oregon. A third introduction was near Brigham City, Utah, about 1910, also from alfalfa seed contaminated with Dyer's Woad seeds. Dyer's Woad spread is associated with travel and commerce of man, and with movement of animals and birds. Seeds are transported by flower collectors, in hay, in crop seed, on vehicle undercarriages, in mud, in debris and many other ways.

ok, from now on I won't believe anything I read, but I have learnt a great deal about Woad.
Thanks all.