In the vascular bundles of the ground tissue the bundle-sheath is rather prominent and the phloëm portion is well developed.
On account of this bundle-sheath the bundles are called fibro-vascular bundles.
|bundle sheath |
A layer or region of compactly arranged cells surrounding a vascular bundle in a plant. The bundle sheaths regulate the movement of substances between the vascular tissue and the parenchyma and, in leaves, protect the vascular tissue from exposure to air.