•0 



DEVELOPMENT OF FORM 



[CH. 



succession. The latter resemble those of the Pines and Firs 

 alrea(3y described in so far that they extend laterally and 

 that the oldest and longest are below, and the youngest 

 and shortest above ; but they differ in being arranged 

 individually at very different levels, though they come off 

 at wide angles. The general effect is to produce the 

 pyramidal or broad-conical form already described, but in 

 a very different manner in detail though the attainment 

 and maintenance of the form are similar in principle, being 

 brought about by the relative growths of the leader and 

 laterals (Fig. 17 i). 



II 



Fig. 17. Plan of development of the Apple-tree type. 



On examining an older specimen of such a tree, how- 

 ever, we find the crown rounded off above and spreading 

 below, evidently owing to the same causes as those 

 already adduced for the rounding off of the Pines, &c., 

 viz. the stoppage of growth of the leader while the lower- 

 most laterals continue to extend as before (Fig. 17 ii). 

 But in other respects the tree is very different ; the stem 

 is no longer traceable to the top, but loses itself sooner or 

 later in the crown, owing to the few main branches which 



