i9i THE STRUCTURE OF ECONOMIC PLANTS 



inner cortical region. Tliis is not a single layer, but consists of a 

 meristematic region adjacent to the cortex. (Fig. 88.) The 

 cortical parenchyma of the adventitious root is continuous with 

 that of the crown stem, and, as the root elongates, it pushes 



j.>.i»»V-.-i^, 





1 mm. 





Fig. 88. Above, transection of stem five months old, slightly below the apical meristem, 

 showing origin of four adventitious roots, R, which are continuous with the outer pro- 

 cambial tissue. The seven cycles of bundles in the stelar portion extend to leaf blades and 

 sheaths, one cycle for each leaf. The vascular bundles of sheath, L, are shown in partial 

 longisection in cortex. 



Below, longisection through apical meristem showing adventitious roots, Ri and R2, 

 apical meristem, X, and vascular bundle of a sheath, L. (After Hoffman.) 



