cambium (vascular, cork)

A cylinder of meristematic plant tissue (lateral meristems) of many woody seed-bearing plants, producing new xylem towards the inside of a plant (stem, root) and new phloem to the outside of a plant (stem, root). The vascular cambium forms tissues, xylem and phloem, that carry water and nutrients throughout the plant. Addition of the new tissue causes the diameter to increase. The cork cambium creates cells that eventually become bark on the outside and cells that add to the cortex on the inside.