Xylem-Water conducting Tissue

continuous system throughout the plant, made of up tracheary elements
have secondary cell wall thickenings that may appear as rings or spirals
tracheids—elongated cells (dead at maturity); usually only type of xylem cell in most gymnosperms and seedless vascular plants
vessel elements—may be wider than tracheids; contain perforations (areas lacking in cell walls), usually on the end walls; more specialized cell type
xylem also has parenchyma associated with it, often found in rays (long strands) & called ray parenchyma