Some plants have sustained empires and sparked wars.
Some have ignited public outrage.
Think tea, opium, tulips-and thistles.
The word 'thistle' refers to a large and widespread group of plants.
In 1852 South Australia passed its Thistle Act, probably the first weed control legislation anywhere in the world.
There are several hundred species within the Asteraceae family, plus a bunch of other plants that are called thistles even though technically, botanically, they're not.
Google 'thistles' .
University Of Western Australia Press Book of thistles: and other prickly subjects, paperback/noelle janaczewska
