INTRODUCTION 3 



ductioii of material vvliich may be employed in the formation 

 of new individuals. These latter are formed in the seeds, the 

 function of which is to perpetuate the species. 



Of the various members of the vegetable organism, the 

 iiowers have the function of producing and developing new indi- 

 viduals or offspring from the organic material with which they 

 are provided. The leaves, on the other hand, are concerned in 

 the production of the necessary food material. This is effected 

 in the green cells of the leaves under the influence of light 

 and from the raw material, which they obtain partly from the 

 atmosphere (carbonic acid), and partly from the soil in the 

 form of mineral salts dissolved in water. It is the function 

 of the roots to fix the plant in the soil, and to absorb from it 

 the soluble mineral salts. 



