Xylem and phloem are two varieties of vascular tissue. Xylem is responsible for the transport of water and dissolved ions from the roots to the rest of the plant. Phloem transports sugars, amino acids, and some ions, from fully developed leaves to developing roots, leaves, and fruits. They typically occur together in vascular bundles within all plant organs. The few plants that lack vascular tissue include moss, algae, lichen, and fungus.