Closed vascular bundles are seen in monocotyledons monocots.
Medullary rays Parenchymatous, found in between vascular bundles.
Structure of Collateral vascular bundle i In this vascular bundle, the phloem lies on the outer side facing the cortex external phloem and the xylem remains towards the pith internal xylem.
Some resin ducts oil ducts in Sunflower are also seen which are surrounded by a ring of glandular cells.