40 ANGLE OF INSERTION [CH. V 



upper parts by insects, wind-breakage, &c., the removal 

 of the powerful competitors for food-materials and water 

 enabling the minute dormant buds to make use of the 

 abundant supplies afforded by the powerful roots. 



These cases are distinct from some others where ad- 

 ventitious buds i.e. buds making themselves evident out 

 of their proper order arise on various parts of the stem, 

 or even the root in exceptional cases, and give origin to 

 shoots in quite exceptional places : these matters will be 

 dealt with elsewhere. 



The angle of insertion of the lateral buds on the long 

 shoots differs considerably in different trees, and it com- 

 monl}^ differs on one and the same shoot at base and apex. 

 For instance, the buds of Lonicera Xylosteum stand out 

 at nearly a right-angle with the shoot, while those of the 

 Black Poplar and many Willows are erect and practically 

 parallel with the shoot bearing them, or they may even 

 have their tips incurved ; those of the Beech diverge at 

 an angle of about 45, and those of the Hornbeam at a 

 smaller angle with the parent shoot. But these angles of 

 divergence are not always constant, and the Hawthorn, 

 for instance, may afford examples where the uppermost 

 shoots stand off at about 60, those lower down at nearly 

 90, while those at the base of the twig may form an 

 even more open obtuse angle of 100 or so. 



On the whole, the upper and stronger shoots make a 

 more acute angle with the forward part of the parent 

 axis than do those low'er down, and although the original 

 angles are not always kept as the shoots age, there can be 

 no question that these general angles of divergence affect 

 the form of branching and of the tree generally, as we 

 shall see when considering that subject. 



