Buds and Methods of Branching . g 



they are opposite, each pair decussating with the pair above and 

 below. 



At a distance of four or five iuternodes from each other, are the 

 scars of the buds of previous winters. By these the amount of 

 growth each year may be determined, also the age of a branch. 



The terminal bud has two axillary buds very close to it. The 

 first internode below the terminal bud did not elongate. 



Two opposite leaf-scars at each node mark the position of the 

 leaves of previous years. The half-dozen dots upon each .scar 

 are the points where the fibro-vascular bundles leading from the 

 stem to the leaf were severed. 



Buds and branches, normally occur in the axils of leaves. When 

 it elongates sufficiently to bear leaves, an axillary bud becomes 

 the terminal one of a branch. 



The number of scales in a bud may be counted, or their num- 

 ber may be determined in buds of previous winters, by counting 

 the scars of the fallen scales. In some cases the internodes 

 between successive pairs of scales have not elongated enough to 

 make the scars distinct. 



The wart-like spots on the bark are lenticels. They admit air 

 to the green tissue below the epidermis of the stem. Their 

 function is the same as the stomates of the leaf. 



A cross-section of the stem will show, (i) the pith at the center 

 (2) a cylinder of wood outside of this, (3) the bark a cylinder 

 surrounding this is green and is covered by a thin epiderms. 

 Between the cylinder of wood and the cylinder of bark is the 

 cambium-layer where growth of the stem in diameter, principally, 

 takes place. 



Sketch a branch (^) including the scars of two previous winter 

 buds ; also a cross-section of the stem, naming parts. 



11. BRANCH OF TULIP-TREE OR WHITE-WOOD. [Lirioden- 



dron tulipifera.) 



At the upper edge of each leaf-scar is a ring running around 

 the stem. This is the scar of the stipules. 



The scales of the terminal bud consist of the two stipules with 

 their edges closely applied together. The outer pair are purple 

 and leathery and not covered with hair as in Magnolia, nor 

 covered with resin as in the Horsechestnut. 



