94 



ROOTS 



When the plant is full grown and shows sign of dying, 

 remove the marble slab and plant together, shaking off the 

 soil and washing the slab with clear water. An etching 

 will often be found showing where each tiny rootlet touched 

 the marble. 



Account for this. 



Prints of such an etching may be made by coating the slab 

 with a mixture of vaseline and lampblack and applying the 

 slab to paper. 



Examine surfaces of rock over which roots have grown. 

 How can we account for the grooves in which such roots lie ? 



85. ROOTS 

 Object. To observe the production of adventitious roots. 



Apparatus. A bottle, water, a branch of willow, poplar, ivy, 

 oleander, or tradescantia. 



Method. Cut the branch with a sharp 

 knife and put it into the bottle full of 

 water. As the water evaporates add more. 

 When roots appear, note where they grow, 

 also the character of such roots and the 

 root hairs which cover them. 



Repeat the same experiment, using 

 leaves instead of branches. The leaves 

 of English ivy and rubber plant are 

 specially good. The top of a pineapple 

 cut off and placed on top of a vessel of 

 water so that the under surface is wet 

 will produce roots in this way. 



Conclusion. How may adventitious 

 roots be made to appear? 



FIG. 35. Adventi- 

 tious roots in water. 



