TIIK NATURE AND WORK OF PLANTS 



108. The plant is a factory which works only by daylight. 

 No starch can be made without sunlight. Sunlight may 

 be looked upon as the power that runs the factory, as 

 steam runs a mill. 



We may carry this comparison further. A shoe 

 factory, besides its power, needs a variety of materials, 

 wood, leather, nails, and so on. If the supply of shoe 

 pegs has been allowed to run out, all the work must stop, 

 though everything else is ready at hand. So, too, the 

 absence of only one of the things needed by the plant 

 factory may cause it to suspend work and die. Sunlight, 

 warmth, water, the various plant foods in available forms, 

 all must be secured in the degree needful. A lack of any 

 one will damage or destroy the crop. 



1. Distinguish between plants and animals. 2. What are the 

 characteristics of protoplasm? 3. Name three parts of a cell. 



4. Compare the parts of a building with the parts of a plant. 



5. Explain how cells are useful to plants. 6. Why do cells divide ? 

 7. Explain how a plant may be likened to a factory. 8. Of what 

 advantage to the plant is it to store up food or energy? 9. Explain 

 how man profits by the tendency of certain plants to store up food. 

 10. Review the uses of water to a plant. 11. Name three gases use- 

 ful to plants. 12. How do plants breathe? 13. Name six mineral 

 substances found in plants. 



HOME EXERCISES 



1. Make an estimate of the number of different plants you can find 

 on your farm. You can readily determine the area of the different 

 fields, and you can count the number of plants in an average square 

 foot of each field. A simple calculation would give you the entire 

 number. 



2. Collect as many different kinds of wood as you can and com- 

 pare their hardness, stiffness, and readiness to split. How does the 

 nature of wood determine its uses for handles, spokes, flooring, and 

 so on? 



