THE ANGIOSPERMAE : ROOTS 



CORTEX 



CAMBIUM 

 SECONDARY CORTEX 



CORK CAMBIUM 



PRIMARY XYLEM 

 SECONDARY XYLEM. 



MEDULLARY RAY 

 SECONDARY PHLOEM 

 COI^K PRIMARY PHLOEM 



Fig. 800. — Diagram to illustrate the process of secondary thickening in a 



dicotvledonous root. 



Cortex 



Endodermis 

 Pericyde 



Protoxylem 



Metaxylem 



Cambium 

 Phloem 



Fig. 801. — Solix sp. Transverse section of the root stele 

 showing the beginning of cambium formation. 



