A lenticel is said to be a porous tissue made up of cells with very large intercellular spaces in the periderm of the secondarily thickened organs, mainly on the stems of woody plants and also on the root of a dicotyledonous flowering plant.
Lenticel formation starts occurring beneath the stomatal complex during the primary growth after the development of the first periderm. As the stems and roots continue to mature, lenticel development continues in the new bark or root.
It functions as a pore, providing a medium for the direct exchange of gases between the internal tissues and the atmosphere.