Vitamin A is derived from beta-carotene and carrots are the leading source of this substance in the American diet. In fact, carotenoids, the group of plant pigments of which beta-carotene is a member, are so named because they were first identified in carrots. This ever-popular vegetable is also a source of disease-fighting flavonoids, and carrots contain a specific type of fiber, called calcium pectate, which may lower blood cholesterol. With the exception of beets, carrots contain more sugar than any other vegetable, which makes them a satisfying snack eaten raw and a tasty addition to a variety of cooked dishes. In fact, some of the nutrients in carrots are more easily absorbed when the vegetable has been cooked, even briefly. The carrot belongs to the Umbelliferae family, and is recognizable by its feathery leaves as a relative of parsley, dill, fennel, celery, and the wildflower Queen Anne's Lace, from which it first may have been domesticated. In earlier times, carrots were small red, yellow, or purple roots; the elongated orange carrot, forerunner of today's familiar vegetable, was probably developed in the seventeenth century. Varieties There are many varieties of carrots, but most of those grown for the American market are 7" to 9" long and 3/4" to 1 1/2" in diameter; carrots of this type are commonly sold in plastic bags at the supermarket. Some stores also offer bunches of carrots with their green tops attached. You may see some less familiar varieties at your local farmstand or farmer's market, including short, fat (but deliciously sweet) Chantenay carrots and small round carrots that are a treat for the kids. Large carrots are sometimes peeled and trimmed to 1 1/2" to 2" lengths and packaged as "baby" carrots. But true baby carrots are pulled from the ground early, and actually look like miniature carrots. They are sold in specialty shops or local markets, usually with their green tops attached.