Confusingly, three different, unrelated plants are all known by this name. The globe artichoke is related to the thistle. Its leaves are edible, as is the bottom part of the flower, called the heart (which you can also buy canned or frozen). The Jerusalem artichoke belongs to the sunflower family and it is the plant’s underground tubers that are eaten. They are rather knobbly and irregular in shape, with a pale brown or purple-red skin. The Chinese artichoke is a perennial herb of the mint family, grown for its edible tuberous underground stems. It has a sweet, nutty taste, similar to the Jerusalem artichoke. It’s much more difficult to find in shops than globe or Jerusalem artichokes.