Zone of cell division
An apical meristem lies under and behind the root cap and, like the stem apical meristem, it produces the cells that give rise to the primary body of the plant. Unlike the stem meristem, it is not at the very tip of the root; it lies behind the root cap. Between the area of active division and the cap is an area where cells divide more slowly, the quiescent center. Most cell divisions occur along the edges of this center and give rise to columns of cells arranged parallel to the root axis. The parenchyma cells of the meristem are small, cuboidal, with dense protoplasts devoid of vacuoles and with relatively large nuclei.
The apical meristem of the root organizes to form the three primary meristems:protoderm, which gives rise to the epidermis; procambium, which produces xylem and phloem; and the ground meri-stem, which produces the cortex. Pith, present in most stems and produced from the ground meristem, is absent in most dicot (eudicot) roots, but is found in many monocot roots.