noun, plural: cork cambiums or cork cambia
A cork cambium is a type of meristematic tissue in many vascular plants. It is in particular a lateral meristem, which is a meristem that is concerned with the lateral growth of plants. The cork cambium is the meristem that is responsible for the formation of cork or phellem in woody trees and certain herbaceous plants.
Initially, a young plant would have an epidermal layer (epidermis) that serves as an outer protective covering. The epidermis would then be replaced by a tougher outermost protective layer of the bark called a periderm. The periderm layer consists of the cork, the cork cambium (also called phellogen), and the phelloderm. The cork cambium, being meristematic, gives rise to new cells. The new cells growing inwards form the phelloderm whereas the new cells growing outwards form the cork (also called phellem).
The cork (phellem) cells replace the epidermis in roots and stems of certain plants. These cells eventually become dead at maturity and become filled with air or with materials, e.g. resins or tannins. The cork is relatively tougher than the epidermis and acts as a better protective barrier against water loss, pathogens, and mechanical injuries.
- bark cambium