<P> The vascular cambium is the main growth layer in the stems and roots of many plants, specifically in dicots such as buttercups and oak trees, and gymnosperms such as pine trees . It produces xylem on the inside and phloem on the outside . In herbaceous plants, it occurs in the vascular bundles which are often arranged like beads on a necklace forming an interrupted ring inside the stem . In woody plants, it forms a continuous ring and grows new wood on the inside . </P> <P> Other names for the vascular cambium are the main cambium, wood cambium, or bifacial cambium . In more detail, the vascular cambium is a plant tissue located between the xylem and the phloem in the stems and roots of certain vascular plants . It is a cylinder of unspecialized meristem cells that divide to form secondary vascular tissues . It is the source of both secondary xylem growth inwards towards the pith, and secondary phloem growth outwards to the bark . Unlike the xylem and phloem, it does not transport water, minerals or food through the plant . </P> <P> Vascular cambia are found in dicots and gymnosperms but not monocots, which usually lack secondary growth . A few leaf types also have a vascular cambium . In dicot and gymnosperm trees, the vascular cambium is the obvious line separating the bark and wood; they also have a cork cambium . For successful grafting, the vascular cambia of the rootstock and scion must be aligned so they can grow together . </P>

Secondary xylem and phloem in dicot stems are produced by