Cichorium intybus, common chicory, is the tough, blue flowered weed growing out of highway medians, and it grows up to about a meter and a half tall and regrows from a low rosette after mowing. Its bitterness comes from lactucin and lactucopicrin, defensive compounds that cooks leach out by boiling the leaves. Selective breeding turned the same species into radicchio, with protected Italian types from Treviso, Verona, and Chioggia. Belgian endive came from an 1850s accident in the Brussels botanical garden, when roots left in a dark cellar sprouted pale, mild leaves.

The roasted taproot became a coffee stand in: Frederick the Great banned coffee imports in 1766, a Brunswick innkeeper opened chicory coffee factories, and by 1795 Brunswick had more than 20. New Orleans used it under Civil War blockade, and East Germany used it in Mischkaffee after the 1976 to 1979 price spike. Around 1970, scientists found fresh roots are 13 to 23 percent inulin, a fiber that feeds gut bacteria and now goes into prebiotic yogurts and bars. Farmers graze bred varieties to fight worms in livestock.

• Belgian endive is still sold wrapped in blue paper to keep store lights from turning it green and bitter.
• Humans cannot digest inulin until gut bacteria ferment it, and hydrolysis turns it into fructose sweetener.
• Condensed tannins in chicory bind to parasitic worms in sheep, cutting their worm burdens.
• New Zealand’s Puna resists bolting and regrows fast, while Forage Feast has lower tannins and Oasis higher lactones.
• Folklore held that chicory cut at noon or midnight on St. James’s Day with a gold blade, in total silence, granted invisibility.