What are cells that cross the phloem and xylem for radial transport called?

Ray cells are specialized parenchyma cells that play a crucial role in radial transport within the vascular system of plants, particularly in the context of the phloem and xylem. These cells are found in both the xylem and phloem and facilitate the movement of water, nutrients, and photosynthetic products across the plant.

Ray cells form a radial system that runs from the center of the stem or root outwards, allowing for the horizontal exchange and storage of materials between the vascular bundles. This is essential for maintaining the health and functionality of the plant, as it ensures that nutrients from the phloem can reach areas of growth and storage in the xylem and vice versa.

While phloem cells and xylem cells are involved in the conduction of nutrients and water vertically within the plant, it is the ray cells that specifically enable this lateral or radial movement. Fibrovascular cells refer to the collective cells comprising both the xylem and phloem but do not specifically designate the cross-connecting function required here. Therefore, ray cells are the correct answer, as they uniquely contribute to the radial transport system in the plant.