Fig. 6.8-2b. Magnification of the center of a root apical meristem of cattail. Even at the very center of the apical meristem, it is possible to distinguish clearly between the root proper and the root cap (arrows). In addition, the cells that give rise to the root cortex (the cortical initials) can be traced to a distinct set of cells just distal to those (the central cylinder meristem) that are producing the vascular tissues (the stele). In the root cap, the columella mother cells produce the central cells (the columella) of the root cap, and those cells in turn produce cells that make up the lateral parts of the root cap.
Many of these zones in the root apex have alternative names; see page 103 in Plant Anatomy (Mauseth) for the other names.