The first cork cambium typically arises in subepidermal cells in stems

Subsequent cork cambia originate in the secondary phloem

Phellogen (cork cambium), in most plants, arises by the periclinal division of subepidermal cortex cells and only the epidermis becomes cut off from the stem as seen in this diagram. At the top, the cork cambium has produced the first cork cell to the outside, and a living phelloderm cell to the inside.

The lower illustration shows the development of the periderm, when cork cambium produced two new layers of the cork but did not add new layers of the phelloderm. Subsequent cork cambia and periderms are formed progressively deeper in the secondary phloem.