Part of the dermal tissue that is made of hard, dead, cork cells is the epidermis periderm cuticle vascular cambium

The periderm is a multilayered tissue that is different from the  epidermis which is single layered. It is made of cork cells (phellem) , phelloderm and phellogen (or cork cambium).

Cork cells are nonliving cells found covering the outside  of roots and stems to provide  protection and  insulation to the plant.

 The periderm serves to protect the plant from injury, pathogens, excessive water loss and provides insulation for the plant.