92 



PLANT LIFE 



made on the whole mechanical system of 

 the plant. If it bends to the wind it ought 



Fig. 13 A. Diagram of transverse section of part of a young 

 stem of sunflower. B, bast ; C, cambium ; Col, collenchyma ; 

 E, epidermis; H, hair; P, pith; E, rind or cortex; Scl, 

 sclerenchyma ; W, wood. 



to recover its old position when the blast is 

 over. Its roots should be able to withstand 

 the stress imposed on them, and prevent the 



