CH. IV, 13) 



ECONOMICS OF STEMS 



209 



technique of grafting centers in making good contacts of 

 cion and stock, and in holding the parts together until their 

 permanent union is effected (Fig. 154). Grafting is mostly 

 done in very early spring, when the tissues are resting, but 

 are soon to become active. Later, as the tissues awaken, they 

 knit together, the wound heals over, and thereafter they 

 grow as one plant, without need of further attention, except 

 that for a time care must 

 be taken to remove any 

 shoots which spring up 

 from the stock, for these, 

 with their greater vigor, 

 may draw all sap from 

 the cion and cause it to 

 perish. Ideally the pro- 

 cess is simplest when cion 

 and stock are the same 

 diameter ; but very small 

 twigs can readily be 

 grafted upon very large 

 stumps. Naturally an 

 elaborate technique and . FIG 154. -illustration of the method 



. I , PI grafting. On the left a cion of apple, 



great Special knowledge prepared; next, two cions inserted in a 



appertain to the subject. s * ock; on the right ' the w . axing f the 



tissues to prevent desiccation and en- 

 Grafting IS practiced for trance of Fungi. (From Bailey.) 



three principal reasons : 



First, and most important, it permits both the preserva- 

 tion and the multiplication of valuable kinds of plants which 

 appear as BUD SPORTS, but which neither transmit their good 

 qualities through seed, nor strike root from cuttings, and 

 hence, except for grafting, would be lost. Bud sports, which 

 are related to monstrosities (page 205), are individual branches 

 which show in their development some striking difference 

 from others on the same plant. Most of our best varieties 

 of Apples, Pears, Oranges, and other fruits, have originated 

 in this way, and are perpetuated only by grafting. Indeed, 



