THE STEM 



241 



naturally becomes conical, the main axis growing stronger than 

 the branches. 



But in ijiany of our ordinary trees the terminal bud of the 

 primary axis develops a flower or perishes, one or more branches 

 continuing the growth of the primary axis in a more or less slant- 

 ing direction, thus giving the crown of the tree a rounded or flat 

 shape (Mango, Poinciana). If only the branch nearest the perish- 

 ed terminal bud is furthered, that branch taking over the direction 

 of the main axis, and this mode is repeated after regular intervals, 

 the main axis is called a sympodhmi. This is seen in any species 

 of the Vine family, 

 where the axis termi- 

 nates successively in a 

 tendril and is continued 

 by the axillary branch 

 growing from the axil 

 of the last leaf pushing 

 the tendril aside. In 

 M i r a b i 1 i s dichotoma 

 (the Four-o'clock 

 plant), on the other 

 hand, the terminal bud 

 dies, and as the plant 

 has opposite leaves, 

 both the axillary buds 

 of the last pair of leaves 

 develop into branches. 

 This is repeated several 

 times, and a, false dicho- 

 tomy is formed. 



Axillary buds often 

 remain latent or dor- 

 mant, until one day 

 the top is cut off, when 

 they awake and begin 

 to grow. Again, twigs which are robbed of light by other branches, 

 starve and die, so that, as the tree grows, many twigs dry up. 



16 



Fig. 218.— A branch of the Grape Vine. 



