Formation of Cork:
Cork is formed from phellogen, which is a type of meristematic tissue found in the bark of woody plants. The phellogen is also known as the cork cambium, and it is responsible for producing cork cells.

Process of Cork Formation:
- The phellogen is a lateral meristem that produces cork cells on its outer side and phelloderm cells on its inner side.
- As the phellogen divides, the newly formed cork cells accumulate on the outer side of the tissue, forming the protective cork layer.
- These cork cells are dead at maturity and have suberized cell walls, which make them impermeable to water and gases.
- The cork layer provides protection to the plant against mechanical injury, desiccation, and pathogens.

Function of Cork:
- Cork cells are tightly packed together, forming a waterproof barrier that helps prevent water loss from the plant.
- The impermeable nature of cork cells also helps protect the plant from pathogens and herbivores.
- Cork is a durable material that has been used by humans for various purposes, such as in wine bottle stoppers, flooring, and insulation.
In conclusion, cork is formed from the phellogen, which is a meristematic tissue responsible for producing the protective cork layer in woody plants. The cork layer plays a crucial role in protecting the plant from environmental stresses and has practical applications in various industries.