Carrots have been grown in Europe and America so long that they've "escaped," as gardeners say. Descendants of the domesticated plant now grow wild as the feathery weed we call Queen Anne's lace. The domesticated carrot would produce big shows of feathery leaves the same as the escaped carrots if gardeners weren't on the job to make it concentrate on large, tasty roots.
Botanists believe carrots were originally domesticated in Afghanistan, which boasts the most varieties in the world. They range in shape from long and thin to quite fat and turnip-shaped. Colors include yellow, white, even purple. (By the way, the orange carrot we're familiar with was developed only about 350 years ago, in Holland. In the Middle Ages, most carrots were the yellow kind, and carrot slices were often put into dishes to represent gold coins.)
No matter what it looks like, every full-grown carrot consists of a thick layer surrounding a relatively woody core. The core is less sweet than the outer part and somewhat bitter, so some recipes suggest removing it. An easy way is to quarter the carrot lengthwise and pick the core out with the tip of a sharp knife.