THE SEED PLANTS 307 



PROBLEMS 



1. In what ways are the seed plants the most complex of all plants? 



2. What different kinds of structures in various seed plants may 

 remain dormant throughout drought or winter, and later continue the 

 growth of the individual plants to which they belong? 



3. Show ten ways in which the seed-plant habit of storing food in 

 seeds and elsewhere is important to industries. What four plants are 

 most valuable for their stored food? 



4. What plant products are being used as substitutes for animal 

 products, as cottolene for lard, etc.? Are there good reasons against 

 such substitution? 



5. How may man vary the amount or quality of food stored in 

 plants? 



6. What cases are there in which man has varied plants until they 

 would probably be unable to maintain themselves in nature if unpro- 

 tected? 



7. What is meant by the statement that the angiosperms are the 

 youngest and most successful group of plants ? 



