Vascular tissue functions in support and long-distance transport of water and dissolved nutrients. It moves the products made and stored in ground tissue. The vascular tissue system is made up of two tissues called xylem and phloem. Xylem conducts water and dissolved ions in one direction: from the root system to the shoot system. Phloem conducts sugar, amino acids, chemical signals, and other substances throughout the plant body. In all vascular plants, xylem contains water- conducting cells called tracheids. In angiosperms and a few other species, xylem contains both tracheids and conducting cells called vessel elements. In angiosperms, tracheids and vessel elements are found adjacent to each other. All xylem cells are dead at maturity and as a result are filled with the fluids that they conduct instead of with cytoplasm. Tracheids are long, slender cells with tapered ends. Their sides and ends have pits where only the primary cell wall is present and where water moves between tracheids.