Pak Choi.
The most typical Pak Choi features dark green leaves atop white spoon-shaped upright stems.
Stems vary considerably in thickness and shape, and in some varieties they are green. One variety produces a rosette of dark green leaves close to the ground.
There are specialty pak chois that have frilly leaves to light yellow-green color.
The slight mustardy flavor of Pak Choi makes it a delightful addition to stir-fries, soups, noodle and meat dishes, and salads, if the young leaves are used.