phellem

This term is a specialized botanical descriptor used primarily in plant anatomy and histology. It refers specifically to the dead, suberized cells that constitute the cork layer, distinguishing the actual tissue from the phellogen (the meristematic layer that produces it) and the phelloderm (the living parenchyma cells produced internally).

Because it describes a specific biological tissue type, it is typically used in academic, scientific, or technical contexts. It is rarely encountered in general conversation, where the simpler term "cork" is preferred.