The strips of Caspary (named after the German botanist Robert Caspary, 1818-1887) are located in the radial and transversal wall of the endodermis .These wall contain suberin and lignin that render them impervious to liquids and gases. Water and minerals can thus only pass to the pericycle by traversing the cytoplasm of these cells. In this way the endodermis builds a selective barrier.