If you’ve ever prepared a globe artichoke, you’ll know the choke: the pale, hairy wad sitting on top of the heart that you scrape out with a spoon and throw away. I only recently learned what it is. An artichoke is a thistle flower bud, picked before it opens. The heart is the base the flowers would have grown from. The choke is hundreds of immature florets, and the hairs are their pappus: the bristles that, left alone, would have dried and opened into the parachutes a seed rides away on. So what goes in the bin is thistledown that hasn’t happened yet.

I’ve spent most of my time on this site with thistles as something you look at. This time I wanted to know what people have done with them. It turns out one thistle has been put to work almost everywhere you look.

One plant, bred twice

The plant is Cynara cardunculus, the wild cardoon, a big grey-leaved Mediterranean thistle. It has been domesticated twice, in two directions. Around the start of the first millennium CE, probably in Sicily, people began selecting it for its flower buds. That line became the artichoke. More than a thousand years later, further west, other people selected it for its leaf stalks. That line became the cultivated cardoon, whose stalks are blanched and cooked a bit like celery. The genetic work treats them as two separate domestications of one species. It’s one wild plant: one crop eats the buds, the other eats the stalks.

The flower that makes cheese

In parts of Portugal and Spain, the flowers are used for something else. Dried and steeped in water, cardoon flowers curdle milk. That’s how Serra da Estrela is made in Portugal and Torta del Casar in Spain, both soft, spoonable ewe’s-milk cheeses. The working part is a set of enzymes called cardosins. Calf rennet trims the milk’s casein proteins at the ends. The cardoon’s enzymes cut them in many places, and that’s part of why these cheeses go so soft and creamy. It’s also why the method mostly stayed with sheep and goats. With cow’s milk, all that extra cutting tends to leave the cheese bitter.

The taste it leaves behind

In 1972, Linda Bartoshuk and colleagues published a short paper in Science about something plenty of people had noticed at the table: after eating artichoke, a sip of plain water tastes sweet. They traced it to two compounds in the plant, chlorogenic acid and cynarin. Neither is sweet itself. They act on the tongue for a while, so the next thing to arrive tastes sweet, and water is the next thing. Not everyone gets it. The paper recorded some people who noticed nothing. I find that strange in a pleasing way: the plant leaves a sweetness behind for something that isn’t the plant.

The one that got loose

The cardoon also crossed the Atlantic with European settlers and went wild. Darwin met it on the Beagle voyage in what’s now Uruguay, and he wasn’t charmed. In one country alone, he wrote, “very many (probably several hundred) square miles are covered by one mass of these prickly plants, and are impenetrable by man or beast.”

And the down

Which left me with the part I started with, the bit that goes in the bin. I’d half expected to be able to write that thistledown was the one thing nobody found a use for. That isn’t true. In his Herball, first published in 1597, John Gerard wrote that thistle down was gathered “as well by the poore to stop pillowes, cushions, and beds for want of feathers, as also bought of the rich Upholsters to mixe with the feathers and downe they do sell.” He called the second use a deceit. A century later, people in London were still being fined over it: in 1690, a John Gatehouse of Fleet Ditch was fined over an old bed stuffed with thistledown and feathers mixed.

So the down did have a use. It was a poor person’s feathers, or a dishonest person’s cheap filler. People gave it jobs, but not as itself, only as a stand-in for something else. The bud became a vegetable, the stalk became a vegetable, the flower became a cheese, and the down, whenever it was used at all, was passed off as a bird’s.

I think I like the down more for that. Every other part of this plant got taken in and made useful. The part designed to leave, the part that exists to ride the wind somewhere nobody chose, is the part we still scrape out and throw away. Left on the plant, it does its own job fine.