What is "endodermis"

Endodermis \En`do*der"mis\, n. [NL. See Endoderm.] (Bot.) A layer of cells forming a kind of cuticle inside of the proper cortical layer, or surrounding an individual fibrovascular bundle.

n. 1 (context botany English) In a plant stem or root, a cylinder of cells the separates the outer cortex from the central core. The endodermis controls flow of water and minerals within the plant. In most plants, this tissue is restricted to the roots. 2 (context zoology English) The deepest layer of the skin.

The endodermis is the central, innermost layer of cortex in some land plants. It is made of compact living cells surrounded by an outer ring of endodermal cells that are impregnated with hydrophobic substances ( Casparian Strip) to restrict apoplastic flow of water to the inside. The endodermis is the boundary between the cortex and the stele.

In many seedless vascular plants, the endodermis is a distinctly visible layer of cells immediately outside the vascular cylinder (stele) in roots and shoots. In most seed plants, especially woody types, an endodermis is absent from the stems but is present in roots.

The endodermis helps regulate the movement of water, ions and hormones into and out of the vascular system. It may also store starch, be involved in perception of gravity and protect the plant against toxins moving into the vascular system.