346 STRUCTURE AND LIFE HISTORIES 



production there is interposed the enlargement or growth 

 of the parent. 



317. Vegetative Multiplication. — Attention has also 

 been called to the various methods by which the number 

 of individual plants is increased by the separation of multi- 



FiG. 252. — Branch of a willow {Salix Sp.), showing the formation of 

 fibrous roots. The lower portion of the stem was placed in water for a 

 few days. 



cellular portions of the body of the parent. The most 

 familiar of these processes being the artificial propagation 

 of plants by rtieans of cuttings. A portion of stem (Figs. 

 3 and 252), or sometimes of leaf (Fig. 253), stuck into 

 moist sand will form new roots and ultimately develop an 



