The chief water-conducting elements of the xylem in gymnosperms are tracheids. These are elongated cells with tapering ends and are dead because of the deposition of lignin. These show scalariform, annular, reticulate, or bordered pitted thickening. These are the only water-conducting xylem elements in both gymnosperms and pteridophytes. Generally, vessels are absent in gymnosperm with exceptions like Gnetum, Welwitschia, Ephedra, etc.