314 



TYPICAL FLOWERING PLANTS 



by a light, buoyant substance, as in the bur reed and the 

 cocoanut, and so may be carried hundreds of miles without 

 injury. In the case of still other fruits, like grains, the 

 whole fruit is eaten, but enough are produced by the plant 

 so that many may be destroyed and yet some be left to 

 serve as seed, and thus prevent the plant from becoming 

 extinct. Squirrels, in storing up food for the winter often 

 bury nuts which are not used, and some of these are sure 

 to grow. 



LABORATORY STUDY OF SEED DISPERSAL 



Every season of the year affords material for this phase of plant study. 

 Record your result as follows : 



228. The Struggle for Existence. — In the process of dis- 

 tribution, six or eight seeds from a plant may fall in al- 

 most exactly the same place. It is probable that all will 

 begin to grow, but only one or two will live, because there 

 will not be sufficient light, food, or moisture for all. In 

 this case the plants which get the best start or have the 

 most vigor crowd out the others. In biology this effort 

 to secure the conditions necessary for life is known as the 

 struggle for existence. The result of this struggle is spoken 

 of as the survival of the fittest. 



