[[1]], also known as thick cork or bark, replaces the epidermis in older plants.k.

Secondary meristem, also known as lateral meristem, is a type of meristem that is responsible for the thickening and increase in girth of stems and roots in older plants. The thickening is accomplished by the formation of new cells, mostly in the form of xylem and phloem tissues, which are produced by the secondary meristem. As these tissues accumulate, they push the epidermis outward, which eventually becomes the outermost layer of the bark.

The cork cambium is a type of lateral meristem that specifically gives rise to cork cells, which accumulate to form the thick, protective outer layer of the bark. Therefore, the secondary meristem does not replace the epidermis, but rather, it produces new layers of tissue that push the epidermis outward and eventually become part of the bark.