The Rhacoma root; a shoddy plant.

This flowering plant is an alien to Britain, its natural distribution being along the banks of the river Volga.
In the past it was the source of important herbal drugs, used to cure a variety of ailments particularly gut, lung and liver problems, especially in China and the far east.
Marco Polo is thought to have introduced the drug to Europe in the thirteenth century when it was known as Rhacoma root. The first time the plant was seen growing in Britain was in the sixteenth century when the seeds were introduced in an attempt to grow and process the drug here. It was so highly regarded and sought after that, in England in 1657  it could command three times the price of Opium.
You have almost certainly eaten your fair share of this plant. Should you need a clue as to its identity the title provides one!