Growth and Movement. 



II 1 



is no cambium zone similar to that in dicotyledonous plants ; 

 but in such monocotyledonous plants as the Aloe and 

 Yucca (6") 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- 



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 Aloe and 

 Yucca 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 



