SURVEY QUESTIONS 



Why are weeds so plentiful? Why do weeds grow in places where 

 other plants cannot exist? Do you know the common weeds in your 

 locality and the ways to eradicate them ? Can you give a scientific defini- 

 tion of a fruit ? Of what values are fruits to plants that produce them ? 



Photo by Wright Pierce 



UNIT IV 



HOW AND WHY DO SEED PLANTS SUCCEED IN LIFE? 



Preview. Our study will now be directed to two main problems ; 

 first, what plants are most successful in their battle of life and, 

 second, what fits them for this success. 



If you will go out any fall afternoon into the fields, a city park, 

 or even a vacant lot, you can hardly escape seeing how seeds are 

 scattered by the parent plants and trees. Several hundred little 

 seedling trees may be counted under the shade of a single maple 

 or oak tree. But nearly all these young trees are doomed to die, 

 because of crowding and lack of sun. Plants, like animals, are 

 dependent upon their surroundings for food and air. They need 

 light even more than animals need it, because the soil directly 



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