268 ELEMENTARY SCIENCE 



Then there are the vines. They climb up the trunks of the 

 trees. They have learned how to take advantage of the 

 work of others. Sometimes in the forest you will find trees 

 covered with vines, weighted down and killed by them. 



In April and early May the leaves are not full on the 

 trees. Light shines through to the forest floor, and this 

 is the season that the little plants of the forest have made 

 their own. In a few weeks they do nearly all their work 

 of growth and of reproduction, and then rest until another 

 season. Nearly all the early spring flowers arise from bulbs 

 or other kinds of thickened underground parts in which 

 food is stored. They do not come from seeds. They shoot 

 right up, and often open their flowers even before the leaves 

 are formed. 



So, as you go about in the woods, you may find a hundred 

 ways in which plants are closely related to their environ- 

 ment. But we do not find that there is just one rule of 

 nature that explains how all these interesting results have 

 been achieved. We know that heredity and environment, 

 working together, have accomplished the results that we 

 see, but we cannot say just what is due to one and what to 

 the other. Certainly plants differ in this matter. Some 

 are much more affected by their surroundings than are 

 others. In this matter, you see, plants are almost pre- 

 cisely like people. We ourselves are the result of our 

 heredity and our experience. We cannot alter our heredity, 

 but we must make our experiences as desirable as possible. 



