THE OPENING OF THE BUDS, CONCLUDED 57 



for its tip also had died before the growing 

 season began. How old, then, is the twig 



Suggestions.— Let the pupil also trace out the history of the hick- 

 ory branch in Fig. 55. Fig. 160, may aid him. Let him explain if 

 the zigzag and tortuous growth of any of the common trees and shrubs 

 is in any way associated with this co-terminal type of fruit-bearing. 



XI. THE OPENING OF THE BUDS, CONCLUDED 



57. If we look again at the opening apple 

 shoot in Fig. 45, we may notice the method of 

 unrolling of the young leaves ; for we have 

 found (50) that the parts in the bud are not 

 only very small, but curiously folded and 

 packed away. The leaf a is seen to be un- 

 rolling outwards from above on each edge. 

 In other words, the leaf was rolled inward on 

 top from both sides, or was involute in the 

 bud. 



58. The expanding shoot of a common honey- 

 suckle is seen in Fig. 56. The successive pairs 

 of leaves are seen at a a, & 6, c c. These leaves 

 are all turned backward, or revolute. Coming to 

 the very tip of the shoot, however (c^), it is seen 

 that the leaves are really involute at first. They 

 become revolute soon after they open. In study- 

 ing the manner in which the leaves are folded in 

 the bud, therefore, it is important that the speci- 



