ACTIVITY OF THE CAMBIUM , 



333 





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rfP^^N 



phloem. ^ 



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ra5 



Sfeconjcfary 

 JtyUm ^ 



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Fig. 54. — Activity of the cambium. A-D, diagrams of cambial 

 cell and its divisions (inner and outer — tangential — ^walls supposed 

 to be transparent, lateral — ^radial — walls opaque). A, single 

 cambial cell seen obliquely from within. B, first tangential 

 division (i). C, second tangential division (2) ; c, cambial cell; 

 X, xylem tissue mother cell ; p, phloem tissue mother cell. D, 

 diagram of tissue mother ceU which has divided horizontally 

 to form a vertical file of short parenchyma cells. E, part of 

 cambium and tissues it has produced as seen in transverse section 

 under high power ; c, cambial cells ; v, xylem vessels ; t, tracheid ; 

 m.r., medullary ray cells ; s.i., young sieve tube ; p.p., phloem 

 parenchyma ; w.p., wood parenchyma ; /, fibres. 



