866 



is a wood body, provided with the peculiarities of the species and isolated in 

 the bark ; its elements grow in all directions around one or more elongated 

 or short cores. 



\ " ....'zhmmmmm^m^^ 



Fig. 20 j. B;iik tulx'is Irom an apple tiunl 



The cambial zone {2 c), surrounding the wood, annually produces a 

 new bark {2 rs) and, in injuries, heals the wounds just as in a normal trunk. 

 Such an injury has taken place in Fig. 204,2 since the bark and sap wood 

 have been removed from the tip of the tuber by some external influence. In 



