Vascular cambium is present between the primary xylem and phloem. The part of the vascular cambium in between xylem and phloem is intrafascicular or fascicular cambium. At the time of secondary growth, the parenchymatous cells of medullary rays between the vascular bundles become meristematic and form a strip of cambium called interfascicular cambium which is secondary in origin. Both the interfascicular and intrafascicular cambium together forms a cambium ring. This cambium ring is partly primary (intrafascicular) and partly secondary (interfascicular) in origin. By the means of periclinal division, the cambium produced the secondary xylem and phloem tissues. Secondary xylem grows towards the inside of the cambium and secondary phloem grows towards the outside of the cambium. The amount of the secondary xylem produced is 8-10 times more than the secondary phloem.