Hurray for "splitters" in every field.
When you really love a field, and pay close attention, nature always rewards us with more and more details to cherish.
Taxonomists seem not to love this kind of diversity!
Apparently the "groups" that used to be in use for discriminating among the thousand-and-one kinds of Brassica rapas weren't scientific enough for SOME scientists, although cooks certainly have no trouble distinguishing between turnips, Chinese cabbage and Tatsoi!
I suppose that if a naming system can't be nailed down tight and any "intermediate" types assigned unambiguously to one sub-group or the other, taxonomists would rather ignore the differences and have a "neat and tidy" system instead of a real-world-useful system. Grumble grumble!
Turnip- - - - - - - - - - - - - - Brassica rapa var. rapa (root and leaves) (sometimes Rapifera group
Chinese Cabbage - - - Brassica rapa (Pekinensis Group) once called celery cabbage
Broccoli Raab / Rapini - - - Brassica rapa (Ruvo Group)
Komatsuna - - - - - - - - - Brassica rapa (Perviridis Group) "Japanese Mustard Spinach"
Tatsoi - - - - - - -- - - - - - - Brassica rapa var. rosularis (Narinosa Group) once called B. Narinosa or B. rosularis
Mizuna - - - - - - - - - - - - Brassica rapa (Nipposinica group) "Japanese Mustard". medium spicy
Bok Choy - - - - - - - - - - Brassica rapa (Chinesis Group)
Choy Sum - - - - - - - - - Brassica rapa (Chinesis Group) small, delicate version of Bok Choy
Yu Choy Sum - - - - - - Brassica rapa (Chinesis or Parachinensis Group) specialized for the tender flowering tips:
Hon-Tsai-Tai - - - - - - a.k.a. B. rapa var parachinensis or B. rapa var purpurea / (Purpuraria Group)
http://en.wikipedia.org/wiki/C...
