lOO 



SIZE OF LEA VES. 



[CHAP. 



relation to the thickness of the stem. This is clearly 

 shown in the following table : — 



Horn- 

 beam. 



Mountain 

 Ash. 



Impression of Stalk below the Sixth Leaf. 



Beech. Elm. Nut Sycamore. Lime. Chestmit. 



• • • o • • 



Elder. 



Ash. 



Walnut. 



Ailanthus. 



Horse 

 Chestnut. 



• • # 



In the Elm the numbers are "ii and 34, in the 

 Chestnut "15 and 72, and in the Horse Chestnut the 

 stem has a thickness of '3, and the six leaves have 

 an area often of 300 square inches. Of course, how- 

 ever, these numbers are only approximate. Many 

 things have to be taken into consideration. Strength, 

 for instance, is an important element. Thus the 

 Ailanthus, with a stem equal in thickness to that of 



