CHAPTER XXX 

 COMPETITION WITH FELLOWS 



375. The Fact of Struggle for Existence. We have 

 seen (Chapter IX) that branches contend amongst them- 

 selves for opportunity to live and grow. Similarly, separate 

 plants contend with each other. We shall observe that this 

 is true; and we are compelled to believe it by considering 

 the efforts that all plants make to propagate themselves. 

 The earth is filled with plants. It is chiefly when plants 

 die or are killed that places are made for others. Every one 

 of these plants puts forth its utmost effort to prepetuate its 

 kind. It produces seeds by the score or even by the thousand. 

 In some cases it propagates also by means of vegetative 

 parts. If the earth is full and if every plant endeavors to 

 multiply its kind, there must be struggle for existence. 



376. The effects of struggle for existence are of three 

 general categories: (1) the seed or spore may find no oppor- 

 tunity to grow, (2) sooner or later the plant may be killed', 

 (3) the plant may vary, or take on new characters, in response 

 to the conditions in which it grows. Consider the crop of 

 seeds that any plant produces: how many germinate? 

 How many of the young plants reach maturity? Note the 

 profusion of seedlings under the maples and elms, and then 

 consider how few maple and elm trees there are. Count the 

 seeds on any plant and imagine that each one makes a plant : 

 where will all these new plants find a place in which to grow? 



377. What Struggle for Existence Is. Struggle for 

 existence with fellows is competition for room or space, 

 for nutrients and moisture in the soil, for light. We may con- 

 sider examples in each of these three categories. 



(218) 



