PINE 67 



The seed-leaves, of which there are usually six, remain for a time 

 in the seed absorbing the food material, and later, when the seed- 

 coat is thrown off, expand as a whorl of needle-shaped green 

 leaves. In the centre of these is the terminal bud, which grows 

 on to form the main shoot of the tree. The main shoot for a 

 number of years bears green needle-shaped leaves, but in time the 

 condition studied in the shoots of the mature tree is established 

 and the long shoots bear only scale-leaves, in the axils of which 

 bi-foliar short shoots stand. Each year the growth of the main 

 shoot adds to the height of the tree, and since a number of branches, 

 which grow in the same fashion, are formed after the first year 

 or two at the upper end of each year's growth, the tree takes on 

 a very regular shape. As it grows, however, the lower branches 

 usually disappear, and the mature condition with a well-marked 

 trunk and a crown of branches is attained. This increase in size 

 and weight would not be possible did the stem and branches not 

 increase in thickness and strength yearly. The yearly additions to 

 the wood are well seen when a tree is cut down, and appear as the 

 annual rings in the wood. By counting these the age of the 

 tree can be ascertained. The root also has branched widely in the 

 soil and fixes the tree firmly, and the main root and its branches, 

 like the stems, grow in thickness. When the tree is from fifteen 

 to thirty years old it begins to flower. The tree attains a height 

 of from eighty to one hundred and twenty feet, and lives for 

 several hundred years. 



