IV. THE ROOTS 



23. Functions of the roots. — The higher plants 

 are generally stationary, and do not move around 

 except in the case of aquatics which float from place 

 to place in currents of water. It was found in 

 previous experiments that water which washed the 

 soil in streams contains certain salts which it has 

 extracted from the soil, and that these salts are nec- 

 essary to make up the food of the plant. Further- 

 more, it will be seen by an examination of a few 

 specimens that the roots are the organs which pene- 

 trate the soil to any depth, holding the plant in its 

 place, and it is through these organs that food salts 

 might be taken up. The root then may be credited 

 with two kinds of work : fixation or anchorage, and 

 absorption of food. 



24. Hoots hold the stem firmly in position. — 

 Grasp the stem of a sunflower, or geranium, or some 

 small plant, and attempt to pull it from the ground. 

 A great amount of force will be necessary, as one 



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