Endoderm

The word endoderm means two different things in embryology and botanics.

Embryology: the endoderm or endoblast is the internal embryonic leaf which forms the digestive tract (except for the mouth and rectum), the digestive glands and the respiratory tract.

Botanical: the endoderm is the innermost layer of the bark of roots. It is a layer of cylindrical cells that lie between the bark and the central cylinder where the vessels that transport sap are found.

The endoderm is a selective barrier that controls movement of substances absorbed from the earth.