20 THE FLOWER GROWER'S GUIDE. 



the organized and constant use of the hose-pipes every early morning and evening during 

 the warm summer season. 



We make a section of a leaf, and then find something like this figure, if we magnify 

 the thin transverse section. At a is a thin layer, of Avater colls, which sucks in the 

 carbonic dioxide (C 0-) from the air through the stomata already mentioned. 



Below, at is a double series of erect or palisade cells, filled with protoplasm 

 and chlorophyll (see page 12). This "living green" cell material has a strong affinity 

 with the carbonic dioxide, and abstracts it from the water cells at «, and by the 

 energ}^ of sunshine this "living green," or chlorophyll, acts chemically upon it, 

 reserving the carbon of which it forms sugar and starch granules (page 19) and other 



necessary materials. 



Then the use of the lower 

 spongy portion of the section at 

 c comes into action. It absorbs 

 all supertiuous water, oxygen, 

 etc., and these are ultimately 

 evaporated through the lower 

 series of cells at (/. In this way, 

 many tons of carbon are taken 

 in by leaves of all plants, espe- 

 cially by the enormous leaf 

 area of oul- largest trees, and 

 tons of water and oxygen are 

 daily evaporated from the leaf 

 laboratories of our woods and gardens, after the elaboration of carbonic dioxide in the 

 way we have shown. 



Under the heading of Eoots, at page 15, you have read of the absorption of water con- 

 taining earth salts in solution, and it is from these simple chemical materials absorbed 

 by root and by leaf that all the manifold vegetable products of the world are made. 



You will now perceive why Euskin, Darwin, and others of our wisest and most 

 thoughtful men have always spoken and written so highly of roots and of leaves. Some 

 of us are apt to think more highly of flowers for beauty, or fruits for use ; but before 

 we can ever have these in perfection the roots and the leaves must be strong and healthy 

 and clean and well fed, both in garden and in the field. 



^bsorpHon surface 



Evapora)ion su?'/ace 

 Fig. 12. Section tr PohTiON of a Leaf. 

 a, water cells ; I, palisade cells ; c, aLsorptioa cells ; d, evnporation 

 cells. 



