STEMS 



377 



BANYAN TREE 



Some of the branches descend and take root in the ground and so appear 



like stems. 



composed of living cells. This is called the cambium layer. 



During the season of growth, these cells are continually 



subdividing and forming new cells, thus adding a ring to the 



thickness of the stem. 



The age of a tree can be 



determined by counting 



these rings. No such 



layers are found in the ^>F^P \ ff IM FT 



monocotyledonous stems. 



Grafting (Figure 115) and 



budding (Figures 116 and 



117) are processes of bringing the cambium layers of two 



trees of similar kinds in contact and keeping them pro- 



tected so that they will grow together. In this way, 



many of our finest species of fruit are propagated. In 



FlGURE 115 



