Thistles are members of the lettuce family and so relatives of salsify and sun-chokes, all of which share a similar flavor. The edible parts of the artichoke are the fleshy bases of the bracts, or protective leaves, and the heart, which is actually the base of the flower structure, the upper part of the stalk. The “choke” is made up of the actual flowerets, which if allowed to bloom turn a deep violet-blue. The small artichokes sometimes seen in markets or in jars come from flowering stalks low on the plant rather than the main stalk. They grow very slowly, and so are picked at an immature stage when there’s little or no choke inside.