Figure 35.18 Primary and secondary growth of a stem (layer 1)

1. (a)Primary and secondary growth in a two-year-old stem 1 Pith Primary xylem Epidermis Vascular cambium Cortex Primary phloem Figure 35.18 Primary and secondary growth of a stem (layer 1)

2. (a) Primary and secondary growth in a two-year-old stem 3 1 2 4 Pith Primary xylem Epidermis Vascular cambium Cortex Primary phloem Xylem ray Growth Phloem ray Cork Primary xylem First cork cambium Secondary xylem Primary phloem Vascular cambium Secondary phloem Figure 35.18 Primary and secondary growth of a stem (layer 2)

3. (a) Primary and secondary growth in a two-year-old stem 6 5 7 8 9 2 3 4 1 Pith Epidermis Cortex Primary xylem Epidermis Vascular cambium Cortex Primary xylem Xylem ray Growth Phloem ray Cork Primary xylem First cork cambium Secondary xylem Primary phloem Vascular cambium Secondary phloem Secondary phloem Periderm(mainly cork cambiaand cork) Growth Bark Primary phloem Primary phloem Layers of periderm Secondary xylem(two years ofproduction) Secondary phloem Vascular cambium Vascular cambium Cork Secondary xylem Most recentcork cambium Primary xylem Primary xylem Pith Pith Vascular cambium Figure 35.18 Primary and secondary growth of a stem (layer 3)