66 



Introduction to Botany, 



insects which are necessary to their cross pollination ; but 

 after fertilization has been achieved and the production of 

 seeds thereby insured, the pedicels turn from the light and 

 deposit the seed pods in the crannies of the rocks, where they 

 may find a suitable place for their germination (Fig. 25). 



47. Formation of Leaves. — We have noticed, in follow- 

 ing the development of seedlings, that leaves are produced 

 at definite intervals along the stem as the shoot elon- 

 gates. The segments of the 

 stem which bear the leaves 

 are called the nodes, while 

 the portions of the stem be- 

 tween the nodes are termed 

 the intemodes. An exami- 

 nation of the apical bud of 

 the shoot, with the simple 

 lens, reveals the fact that 

 the leaves are begun as lat- 

 eral outgrowths of the stem 

 quite close to the growing 

 point, the apical bud consist- 

 ing, in fact, of a succession 

 of immature nodes, inter- 

 nodes, and leaves. 



48. Summer and Winter Buds. — In some plants, the 

 growing point of the shoot continues to give rise to new 

 nodes, internodes, and leaves throughout the growing sea- 

 son, so that when winter sets in there is a certain unripe 

 portion of the shoot extending back from the apex which 

 is killed by the cold, or its buds are weak, and the continu- 

 ation of growth the following season devolves on buds on 

 older portions of the stem. In such plants the crown is 

 much branched and has no main central trunk (see Fig. 26). 



Fig. 26. 



Honey locust with deliquescent trunk. 



