phelloderm

This term is a highly specialized botanical descriptor used almost exclusively in plant anatomy and histology. It refers to the living tissue layer that supports the development of the periderm, the protective outer bark of woody plants. Because it describes a specific biological structure, it is used in a technical, scientific register rather than in general conversation.

In a botanical context, it is often discussed alongside the phellem (cork) and phellogen (cork cambium). Together, these three components constitute the periderm. The phelloderm is distinguished by its role as the innermost layer, consisting of parenchyma cells that provide structural and metabolic support to the outer tissues.