refer to both groups of B. rapa . The name bok choy and its variations bok choi and pak choi are all taken from the Cantonese readings of the name. [ See also Kai-lan (Chinese broccoli) External link Nutritional information on bok choy (with photo of chinensis variety)  ( http://www.wholehealthmd.com/refshelf/foods_view/1,1523,148,00.html )