Keiseiso
The keiseiso, or cambium, is a structure of dividing tissue that promotes growth of stems and roots. It is located in a vascular bundle between the xylem and the phloem. Tsugiki grafting occurs when cambiums of daiki (stock used for grafting) and hogi (daiki-grafting branches) conjugate. All cambiums are removed when kanjo habuhi or circular decorticating is conducted.
translated by Kyodo News