What is peridem ? How does peridem formation take place in the dicot stems ?

Explanation

A. Phellogen, Phellem and Phelloderm are collectively known as periderm.
(1) Due to the formation of more secondary vascular tissues a pressure is exerted on the epidermis causing its rupture. So a secondary protective layer (periderm) is formed.
(2) Parenchyma cells in middle or inner cortex dedifferentiate into a ring of secondary meristem. This is called cork cambium or phellogen. It cuts off new cells on both sides.
(4) Tissue produced on outside is called cork tissue or phellem. Tissue produced inside is called secondary cortex or phelloderm.
(4) The. phellogen, phellem, and phelloderm together constitute periderm.

(5) To facilitate gaseous. exchange in the cork tissue certain bulged lens shaped structures are formed. They are called
lenticels.