n8 THE VEGETATIVE ORGANS 



of dwarf shoots with crowded leaves, while the buds at the 

 ends of the dwarf shoots of previous years have each de- 

 veloped several leaves, also crowded together, owing to the 

 slow growth of their internodes. If you examine several twigs 

 of the Beech, you will find that, while the end bud may grow 

 a foot or more in a season, a dwarf shoot may have grown 

 only three inches in ten or more years. 



Scots Pine. An excellent example of the development 

 of dwarf shoots is seen in the Scots Pine (see Fig. 182). 

 Examine a small branch, and you will find that it is 

 terminated by a large bud, round the base of which are 

 three or four smaller lateral buds standing at nearly the 

 same level. Farther back the axis appears to be covered 

 by tough evergreen needle-leaves. Carefully examine the 

 shoot to see where and how the needles arise. Do they 

 spring, like many leaves we have seen, singly from the axis ? 

 Remove a few of them. Do they come away singly, or in 

 pairs ? Can you find any other structure on the axis still 

 remaining when the needles have been removed ? Examine, 

 and compare with this, part of a branch from which 

 the needles have fallen off naturally. What are the 

 structures producing the roughness of the shoot ? Are the 

 pairs of needles related in any way to similar structures ? 

 If any doubt as to the last -mentioned point remains, the 

 examination of an elongating bud in the spring will make 

 their relationship clear. The axis produces only scale- 

 leaves. In their axils, buds arise which form very short 

 shoots (dwarf shoots). At the base of each are several 

 scale-leaves, and near the tip are two long, green needles. 

 Such short shoots are called ' bifoliar spurs ' (see Fig. 179) . 

 They remain three or four years on the tree, and are then 

 thrown off. Each year new ones form, so that the tree is 

 always green. Examine the ground under a pine tree 

 and pick up a few of the old needles. Does the pine shed 

 merely its leaves or its short branches also ? We see that 



