II. THE KOOT. 37 



side them, but by closer bond, bud springing forth from 

 root, and the young plant being animated by the gradu- 

 ally surrendered life of its parent. Sometimes the young 

 root is formed above the old one, as in the crocus, or be- 

 side it, as in the amaryllis, or beside it in a spiral succes- 

 sion, as in the orchis ; in these cases the old root always 

 perishes wholly when the young one is formed ; but in a 

 far greater number of tribes, one root connects itself with 

 another by a short piece of intermediate stem ; and this 

 stem does not at once perish when the new root is formed, 

 but grows on at one end indefinitely, perishing slowly at 

 the other, the scars or ruins of the past plants being long 

 traceable on its sides. When it grows entirely under- 

 ground it is called a root-stock. But there is no essential 

 distinction between a root-stock and a creeping stem, only 

 the root-stock may be thought of as a stem which shares 

 the melancholy humour of a root in loving darkness, while 

 yet it has enough consciousness of better things to grow 

 towards, or near, the light. In one family it is even fra- 

 grant where the flower is not, and a simple houseleek is 

 called ' rhodiola rosea,' because its root-stock has the scent 

 of a rose. 



16. There is one very unusual condition of the root- 

 stock which has become of much importance in economy, 

 though it is of little in botany ; the forming, namely, of 

 knots at the ends of the branches of the underground 

 stem, where the new roots are to be thrown out. Of these 

 knots, or c tubers,' (swollen things,) one kind, belonging to 



