Bok choy is a variety of Chinese cabbage. It has long, white, celerylike stalks and large, dark green leaves and its flavor is much like mild cabbage. Ripen green or yellow plantains at room temperature. It has a light licorice flavor that mellows upon cooking. It is sold whole as dried berries or ground.
Coriander seeds are from the cilantro plant.
It is sold as seed, whole, or ground. It is sold as rolled dried sticks or ground. Sometimes it's available pre-grated in the dairy or deli department of the grocery store. Look for them in packaged singly in a stack or in perforated sheets of three. Some markets will cook it for you while you wait.