Question

Formation of vascular rays occurs in which order

Answer 1

it occurs in thevascular bundles which are often arranged like beads on a necklaceforming an interrupted ring inside the stem. ... In more detail, the vascular cambium is a plant tissue located between the xylem and the phloem in the stems and roots of certainvascular plants.

Answer 2

Generally xylem and phloem is formed from the maximum part of the vascular cambium and medullary rays are  formed  from the few parts of vascular cambium. But in some plants parenchyma (Medullary  rays) is formed from the maximum part of the vascular cambium and rarely in some places xylem and phloem are  formed.