Conductive vessel element in mountain mahogany wood (Cercocarpus sp), coloured scanning electron micrograph (SEM). Note the bordered pits in the cellulose wall. A conductive vessel element is an elongated, water-conducting cell in the xylem, one of the two kinds of tracheary elements. The cells die when mature, leaving only their lignified cell walls. They are stacked one on top of another in long columns, called vessels. Water flows unimpeded from cell to cell along these columns through perforations in the cell walls. Vessel elements are found only in angiosperms. Magnification: x98 when shortest axis printed at 25 millimetres.