In land plants, the endodermis is the core, deepest layer of cortex.
It is a cylinder of compact living cells with hydrophobic material (Casparian strip) deposited on the radial walls to prevent apoplastic water flow into the interior.
In the roots, the endodermis is found between the vascular tissues and the cortex.
It forms the cortex's inner margin.
Due to the presence of suberized Casparian strips, it is water impervious.
It functions as an apoplastic barrier, regulating the flow of water and nutrients throughout the vascular system.
To reach the xylem, water must go through the symplastic pathway.
Endodermis prevents water from leaking back into the vascular system.