Lenticel

A lenticel is a porous tissue consisting of cells with large intercellular spaces in the periderm of the secondarily thickened organs and the bark of woody stems and roots of dicotyledonous flowering plants. It functions as a pore, providing a pathway for the direct exchange of gases between the internal tissues and atmosphere through the bark, which is otherwise impermeable to gases. The name lenticel, pronounced with an [s], derives from its lenticular (lens-like) shape. The shape of lenticels is one of the characteristics used for tree identification.

Formation

Lenticel formation usually begins beneath stomatal complexes during primary growth preceding the development of the first periderm. Lenticels are found as raised circular, oval, or elongated areas on stems and roots. As stems and roots mature lenticel development continues in the new periderm (for example, periderm that forms at the bottom of cracks in the bark). Lenticels are also found in pneumatophorous roots (respiratory roots).