Medullary ray or pith rays They are the radial strips of parenchyma cells present between the adjacent vascular bundles. The medullary rays connects the pith with pericycle and cortex. They ray cells make intimate connection with the conducting cells of both xylem and phloem through pits

The medullary rays help in the radial conduction of food and water. They also transport gases from pith to cortex and vice-versa