136 



PLANT LIFE. 



the leaves are placed alternately along them. The 

 arrangement in the case of the Beech is perhaps the 

 simplest and most effective, and its shade is certainly 

 very complete, for practically nothing is able to grow in 

 a close plantation of beeches except the seedlings of 

 the plant itself. The twigs are not quite straight, but 

 zigzagged. The zigzag is occupied by the upper basal 

 margin of a leaf, the rest of the upper margin being 



P"iG. 15. — Leaf of Limetree. 



next the lower basal part of the leaf above and fitting 

 closely to it. The outer terminal part of the lower half 

 of the leaf has a shape probably determined by con- 

 siderations connected with the weight of the leaf, though 

 the outline bulges out in this part as far as it can. 



In the Lime the twig is nearly straight, but the 

 leaves have rather long stalks, and are unsymmetrical 

 at the base, one base-half, the farthest from the stem, 

 starts with a wide lobe which covers the space between 

 its own stalk and the twig and the stalk of the leaf 



