Fig. 6.—Section showing central part
Fig. 6.—Section showing central part of an older root in which the secondary changes have made further progress. Magnification, 110 diameters.
a, parenchyma cell of cortex;
b, cell of endodermis;
d, meristem now traceable as a cambium zone;
e, outer extremity of xylem ray;
f, starch-bearing cells formed beneath pericambium;
g, cambium opposite outer end of xylem ray;
h, new ducts in process of formation, the beginning of the secondary xylem.