7i8 



A TEXTBOOK OF THEORETICAL BOTANY 







Fig. 720. — Cycos revohita. Transverse section of a petiole 

 showing numerous vascular bundles in a convoluted 

 arc. 



Centripetal xylem m,Z— 

 Protoxylem 



Centrifugal xylem 

 Cambiun-i 



Phloem 

 Fibrous sheath 



r-^ 



k» ir 1^ 



Fig. 721. — Cycas revoluta. Transverse section of a 

 single bundle from the upper part of a petiole 

 showing the considerable development of centri- 

 petal xylem and diminution of centrifugal xylem. 



