126 



ROOTS 



B. Secondary Roots. — These come from the stems or 

 leaves. Creeping or subterranean stems usually give off 

 roots at their nodes. Strawberry and grass stems are 

 examples. The creeping stems of the strawberry are 

 .,.:.^ called runners. At their 



nodes the runners may 

 develop both roots and 

 shoots and thus estabUsh 

 new independent plants. 

 (See Figure 40.) 



Berry bushes are some- 

 times reproduced by a 

 process called layering. 

 Layering consists in bend- 

 ing down the yielding 

 outer stems of the berry 

 bushes and covering them 

 with soil. From the 

 buried nodes roots and 

 shoots arise. Presently 

 a new little plant is thus 

 established. It is then 

 cut away from the parent 

 stem and transplanted. 

 The black raspberry 

 spreads by means of new plants which arise naturally from 

 the ends of its trailing branches. 



Some secondary roots have special functions ; that is, 

 their work is quite different from the work usually done 

 by roots. The prop roots of corn are examples of this. 

 (See Figure 4, page 48.) They rise from the first node 

 above the soil and sometimes from the second node as well. 



Fig. 3g. 



- Dandelion showing the tap-root. 

 Redrawn from Bailey. 



