ROOTS 61 



73, Propagation by Means of Roots. Some familiar 

 plants, such as rose bushes, are usually grown from roots 

 or root-cuttings. 



Bury a sweet potato or a dahlia root in damp sand, and watch 

 the development of sprouts from adventitious buds. One sweet 

 potato will produce several such crops of sprouts, and every sprout 

 may be made to grow into a new plant. It is in this way that the 

 crop is started wherever the sweet potato is grown for the market. 



74, Tabular Review of Experiments. 

 [Continue the table begun at end of Chapter III.] 



75, Review Summary of Roots. 



Kinds of roots as regards origin . . . . . 



Kinds as regards medium in which they grow . 



Structure of root of a tree. 



T mate rials. 

 Storage in roots *{ location. 



louses. 



f apparatus. 



amount. 



Absorption of water by roots ^ 



I proofs. 



^causes. 



f nature. 

 Movements of roots J cause s. 



I uses. 



