I70 PLANT LIFE. 



into an almost vertical position on the extreme outside 

 of the foliage dome. 



Both stem and branches have a natural bent, or 

 tendency, to grow upwards, and to turn towards the 

 light Thus a young branch, starting inside under the 

 shade of the older ones, grows outwards at an inclined 

 angle. It compromises between the vertical position and 

 the direction (the outside of the tree) from which light 



Fig. 22. — Diagram to show Tree Branches (see text). 



is coming (Fig. 22). Thus one would expect a straight 

 line uniting the points, a — b, but the result is a curve, 

 which is infinitely more graceful. This is probably, 

 as has been shown by Professor Henslow, due to the 

 weight of the branch, which acts as a heavy weight 

 hung at the centre of gravity {c in upper branch) would 

 do, bending up the part a, and bringing the centre of 

 gravity nearer the stem. In all trees the branches 

 turn upwards as soon as they get out of the shade of 

 the older ones. 



