WOODY PLANTS. 
139 
EXERCISE XLVII. 
Parts of a Tree, 
Trunk. —The main stem of a tree. 
Head. —The branching top of a tree. 
Observe the varying lengths of the trunks in the 
trees about you, Measure the size around their trunks 
Fig. 233. 
Head. 
Trunk. 
at different heights from the ground. Judge as well 
as you can at what distance from the ground the 
lowest limb starts from the trunk. Then test your 
judgment by measuring. 
If you call the branches that start from the trunk 
primary, the branches which these put forth may be 
called secondary branches, and those given off next 
would be tertiary branches. In observing the heads 
of trees, fix your attention upon a primary branch, 
and see if you can find these divisions. Observe 
whether the tertiary branches bear still other branches. 
