Fig.
6.8-2d. Magnification of the boundary between the root cap and root
proper near the apical meristem in cattail. The prominent row of flat,
brick-shaped cells is the protoderm
(between arrows), and for the entire distance here, it is a uniform layer,
distinct from the root cap. Because it is so distinct, this is a closed
root apical meristem. The cells of the root proper have been dividing so much
that they are still small, despite the fact that they have also been enlarging,
whereas the cells in the root cap have undergone many fewer divisions, so they
are much larger.