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 means 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 



