Brassica rapa
Bok choy (American English), pak choi (British English), pichay/petsay (Filipino), or pok choi ("Brassica rapa" subsp. "chinensis") is a type of Chinese cabbage. "Chinensis" varieties do not form heads and have green leaf blades with lighter bulbous bottoms instead, forming a cluster reminiscent of mustard greens. "Chinensis" varieties are popular in southern China, East Asia, and Southeast Asia. Being winter-hardy, they are increasingly grown in Northern Europe. Now considered a subspecies of "Brassica rapa", this group was originally classified as its own species under the name "Brassica chinensis" by Carl Linnaeus. They are a member of the family of Brassicaceae or Cruciferae, also commonly known as the mustards, the crucifers, or the cabbage family.