Growth and Movement. 



in 



is no cambium zone similar to that in dicotyledonous plants ; 

 but in such monocotyledonous plants as the palm and smi- 

 lax (C) a zone of cells near the periphery of the stem 

 remains in a dividing condition indefinitely, and thus adds 

 to the diameter of the stem, some of the cells of the periph- 



FlG. 47. 



Diagrams showing regions of continued growth in dicotyledonous and monocoty- 

 ledonous plants. The shaded regions are capable of growth. A, a Monocoty- 

 ledon of the grass type, growth taking place at the apices of the stem and roots 

 and at the bases of the younger nodes ; C, a Monocotyledon of the palm and 

 lily type, the apices of the stem and roots and a zone (/) near the periphery 

 being in a growing state; B, a Dicotyledon, growth taking place at the apices of 

 the stem and roots and at the cambium ring (z). 



eral zone undergoing the necessary modifications to form 

 new vascular bundles. 



In such monocotyledonous stems as those of grasses (A), 

 increase in length is also brought about by the division of 

 the cells at the base of each node, which retain the power 



