Periderm is the secondary dermal tissue on stems and branches of woody plants. The periderm is developing when the epidermis (primary dermal tissue) rips due to secondary growth. The periderm is mostly smooth and slightly structured. At maturity, it is typically replaced by the bark (tertiary dermal tissue) in most species. The periderm remains for a long time only in few species (e. g. in Fagus – Beech).