Rhytidome structure: Schematic diagram

Complex dead tissue

Sequent periderm

A diagrammatic representation of rhytidome structure in English oak (Quercus robur) showing the first layer of periderm and the sequent layers which may appear later in the same year of growth, or in subsequent years. The sequent layers may anastomose, and arise from secondary phloem parenchyma and cells of the expanded phloem rays.

A rhytidome has a complex histological composition. It consists of alternating layers of cork which enclose dead tissues of the bark.

P = periderm (cork), RP = remnants of primary phloem, RS = remnants of secondary phloem, F = fiber, and D = druse