Brassica rapa pekinensis
An easy-to-grow barrel-head type for late summer and fall planting. Mild flavor, crunchy texture, like an "iceberg" cabbage. Not a good spring crop--likes decreasing temperatures and day lengths, and tends to bolt if temp or light increases. Delicious fall salad green, very juicy, as well as for soups, steaming, stir-fry, and making kim-chee.