Meristematic (cambium) layers of cells with the power of division lying between the phloem and xylem in vascular bundles/veins. Give rise to secondary thickening in dicot stems. In horticulture allows for cuttings to root or grafts to join: Living cells. Incompletely or not at all differentiated. Capable of continuous cellular division. Small cells. Protoplasm fills cell completely. Extremely small vacuole. Packed closely together without intercellular cavities. Cell walls very thin – primary cell walls.