The characteristics of cork are as follows
(a) Cells of cork are dead at maturity
(b) These cells are compactly arranged
(c) Cells do not posses intercellular spaces.
(d) Cells possess a chemical substance ‘suberin’ in their walls.
(e) There are several thick layers.
As plants grow older, a strip of secondary meristem replaces the epidermis of the stem. Cells on the outside are cut off from this layer, This forms the several-layer thick cork or the bark of the tree.