THE ARROW-HEAD. 77 



which can behold unmoved the gorgeous-colored drapery which 

 Autumn throws so lavishly over our American forests. 



To the life of the plant the leaves are of the first importance, 

 quite as necessary as its roots. The roots suck up great quantities 

 of water from the soil which holds in solution various chemical ele- 

 ments necessary for the life and upbuilding of the plant. Most of 

 these must be brought in contact with the air and other chemical 

 agents, before they can be assimilated into the woody and other 

 tissues of the plant. The leaves are the principal organs for ac- 

 complishing this. They serve indeed in the double function of 

 organs of respiration and digestion. 



They are made up of layers of minute cells containing a green 

 substance called chlorophyl, together with bundles of woody tissue 

 which constitute the frame-work or skeleton. Upon the underside 

 of most leaves the microscope reveals thousands of little pores or 

 mouths opening through the cuticle into the interior of the leaf. 

 These openings are for breathing. The air goes freely in through 

 these, and circulates among the interstices of the cells. The car- 

 bonic acid of the air is decomposed by contact with the green 

 contents of the cells, the carbon being kept and wrought up into 

 vegetable fibre and the oxygen partly breathed out again, and partly 

 used up in making other chemical compounds with the fluids that 

 have come up from the roots. These fluids then flow back into the 

 body of the plant and enter into various vegetable substances and 

 tissues. So we see that the leaf serves the plant in the double 

 capacity of lungs and stomach. 



The different forms of leaves are almost endless, varying from 

 the simple needle of the pine to the elaborate compound leaf of the 

 horse-chestnut, locust, or fern. Almost every conceivable shape 



