4 A TEXT-BOOK OF BOTANY 



tions; and a plant with several organs has so many delicate 

 adjustments to care for that it is impossible, as yet, for us 

 to explain why all of its parts are placed just as they are. 



7. Some conspicuous organs. The prominent plants, 

 which are spoken of as herbs, shrubs, and trees, have three 

 conspicuous organs, root, stem, and leaf, which are con- 

 cerned with nutrition; and most of these plants have at 

 some time also another structure, the flower, which is con- 

 cerned with reproduction. Our first attention will be given 

 to these three great nutritive organs. A tree, for example, 

 has its roots extending more or less widely through the soil; 

 from the roots a stem rises into the air and branches more or 

 less extensively; and upon this stem or its branches leaves 

 are borne. Such is the general plan of the more complex 

 plants; and our first purpose will be to discover what these 

 organs are doing, and why they are so related to one another 

 and to their surroundings. 



