Phloem is a tissue that conducts the sap produced by vascular plants. This tissue consists of living cells that are stretched out in a tube shape (graded cells), associated with companion cells, parenchyma cells and liber fibres.
Depending on where it is formed, there is primary phloem, produced by procambium, or secondary phloem, produced by cambium and found only in dicotyledons.
A tinted cross section of a stem. The arrow indicates the phloem, which conducts the elaborated sap. © Clematis, Wikimedia CC by-sa 3.0