It is not clear whether Chinese white cabbage is bok choy or Chinese leaves and may probably refer to either. Bok choy is a variety of small Chinese leaves with thick, long, narrow, bright green leaves held loosely on crunchy white stalks. It can be eaten in salads when young. Alternatively it is Chinese cabbage, a large, very pale green head of a vegetable, resembling a dry Cos lettuce. These are used in stir fries, and sometimes pickled.
