THE SIGNIFICANCE OF LEAVES. 



797 



acterized. A peculiarity of opposite style is presented in the leaf 

 of the tulip tree, which is unique in shape, being cut off at the 

 end and having a marked hol- 

 low or notch where nearly 

 every other leaf is angular or 

 convex. 



Our space is filled, and we 

 have said nothing of the pin- 

 nate leaves, or the spiny leaves, 

 or the leaves of the spruces and 

 firs, of all of which as interest- 

 ing studies might be made. 



The greatest sphere of use- 

 fulness which a tree occupies, 

 Mr. Mathews says, is connected 

 with its life. It is a great air 

 purifier; it absorbs from the 

 atmosphere the carbonic- acid 

 gas which is poisonous to us ; 

 it holds and slowly dispenses 

 moisture which the parched air 

 needs ; it gives out the ozone 

 (or oxygen in an active electro- 

 negative condition) which is 

 peculiarly conducive to our 

 health; and it modifies heat 

 which would otherwise be over- 

 powering. Each leaf is a build- 

 er up and an air regulator of a 

 nature which is beneficial to 

 us. " Its capacity for heat and 

 sunshine is something astonish- 

 ing. I have estimated that a 

 certain sugar maple of large 

 proportions, which grows near 

 my cottage, puts forth in one 

 season about four hundred and 



thirty-two thousand leaves ; these leaves combined present a sur- 

 face to sunlight of about twenty-one thousand six hundred square 

 feet, or an area equal to pretty nearly half an acre. Every inch 

 of this expanse breathes in life for the tree, and out health for 

 man, while it absorbs in the aggregate an enormous amount of 

 heat and sunlight. In time of rain it also holds the moisture, 

 and allows it to evaporate by slow degrees when hot days re- 

 turn. The forests are vast sponges, which, through the agency 

 of leaves, soak up the beneficent raindrops and compel them 



Fig. 6. Red Mulberry. 



