The cambium present within the vascular bundle is called intra fascicular cambium or vascular cambium. It is present between the primary xylem and primary phloem. The intra fascicular cambium is primary in origin.
The new strip of cambium which is formed from the permanent cells of inter fascicular parenchyma is called the inter fascicular cambium. The inter fascicular cambium is secondary in origin since it is derived from the permanent cells of medullary rays.