ANATOMY OF STEMS 



219 



face (Fig. 55). Secondary growth of woody stems is initiated during the 

 first season of their development, and continues during each growing season 



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\ cortex 



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 comd/um 



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Fig. 54. Segment of young stem of tulip poplar {Liriodendron tulipifera) as seen in 



cross section. 



thereafter. Hence after a few years the great bulk of any woody stem is 

 composed of secondary tissues. The apical and diameter growth of woody 



