Exodermis An outermost layer of thickened or suberized cortical cells that sometimes replaces the epidermal layer in the older parts of roots if the epidermal cells have died.

• 外皮层：薄的或木栓化的皮层细胞的最外层。如果根的较老部分表皮细胞死亡，它通常取而代之。