Which among these vascular bundles can continue to generate xylem and phloem?

Vascular bundles of dicot stem have primary meristem known as fascicular cambium which helps in the formation of further formation of xylem and phloem. Since the vascular bundles of root and monocot stem do not have any meristem, they cannot on their own add vascular tissues unless some other tissues other than vascular bundles are involved.