From the Wikipedia entry on this invasive weed:
Onopordum acanthium (Cotton thistle, Scotch thistle), is a flowering plant in the family Asteraceae. It is native to Europe and Western Asia, from the Iberian Peninsula east to Kazakhstan, and north to central Scandinavia, and widely naturalized elsewhere. It is a vigorous biennial plant with coarse, spiny leaves and conspicuous spiny-winged stems.
In the late 19th century, it was introduced to temperate regions of North America, South America, and Australia as an ornamental plant and is now considered a major agricultural and wildland noxious weed. It has been recorded from nearly 50 countries. It is difficult to eradicate because of its drought resistance. It can spread rapidly and eventually dense stands prohibit foraging by livestock.