32 JBotanig 



In all woody stems, the growth of the year is not 

 only in height but in girth ; next the bark there is 

 produced a new ring of material each y63ar. Examine 

 a log that has been cut smoothly across ; you w411 

 find that from the centre to the l)ark it is a series of 

 rings. These rings are of unequal width. The 

 narrow rings represent dry seasons, where the tree 

 had not enough moisture to grow rapidly ; the wide 

 rings speak of seasons when the conditions of growth 

 were better. Thus the tree writes the history of the 

 seasons through which it has passed. 



The young stem lifted into the air differs very 

 markedly from the root, in that the tip of the root 

 is covered with a protective, horny cap, w^hile the 

 growing point of the stem has no such cap. The 

 apex of the stem is a bud ; this bud is more or less 

 closely wrapped in scales, which seem to be covered 

 wdth a thin varnish to protect the bud from too much 

 moisture. The growth of the stem presses this bud 

 upward, the scales unfold, the bud opens, leaves and 

 branches are formed. New leaves are sent forth at 

 the axils, but the growing point, the bud at the apex, 

 is still the top of the plant. 



If this apex is cut off it is not replaced by a new 

 one, but the vitality of the stem deprived of this 

 point of activity, throws out fresh branches lower 

 down, 



