THE SYCAMORE "KEY" 



skin, which has now become soft and decayed. 

 This shoot is the root of the young sycamore plant 

 just beginning to seek for moisture and mineral 

 substances. In the two upper examples of the 

 figure the root is seen developing from the seed. 



On the opposite end to this root are two large 

 and carefully-folded green leaves, and as the young 

 root penetrates the soil, they begin to unfold and 

 spread themselves out to the sunlight. They, like 

 the root, are seeking food ; for these leaves can 

 assimilate food material from the atmosphere. In 

 the two lower examples of the figure the leaves 

 are shown unfolding, the final one showing the 

 wing completely thrown off, leaving nothing but 

 the shrunken base still adhering. 



The young root works its way amongst the 

 interstices of the soil, and sends up supplies of 

 moisture and mineral matters in solution to the 

 niirse-leaves, which, however, are not the true 

 leaves of the plant ; indeed it only needs a glance 

 at their shape as they unfold to see that they are 

 quite unlike sycamore leaves. In Fig. 9 (Plate 7) 

 we see them at the next stage, the example on 

 the right being fully expanded. 



The function of the nurse-leaves thenceforth is 

 to assimilate carbon from the impurities of the 

 atmosphere, or, technically speaking, from the 

 carbon dioxide of the atmosphere, the poisonous 

 gas which we exhale in respiration, and thousands 

 of tons of which are passed into the atmosphere . 

 from the chimneys of manufacturing works. The 

 carbon derived in this way is chemically combined 



21 



