Cork is formed from [[1]].

Cork is indeed made up of a layer of cambium that forms as a secondary meristem from a layer of living cells just beneath the epidermis. However, this layer of cells is not Collenchyma or Parenchyma, but rather the Phellogen or cork cambium itself. The cork cambium divides and produces cells that mature into cork cells towards the outer side and cells that differentiate into phelloderm cells towards the inner side. The cork cells are dead at maturity and have a waxy suberin layer in their cell walls that make them impervious to gases and water. The cork cells protect the underlying tissues from damage, pathogens, and water loss.