4 PEACTICAL BOTANY 



plant structures and processes are of importance primarily for 

 their function in maintaining the life of plants themselves, and 

 that their use in the industries is a by-product of plant life. 

 The body of a tree is produced in the tree's ordinary processes 

 of growth, and thereafter it chances to be useful to men for 

 timber. Though corn and wheat have been improved artifi- 

 cially until now they supply much of the food of mankind, in 

 nature as wild plants they produced seeds which were small 

 but sufficed to give rise to new plants. The possibilities of 

 utility result from the ordinary activities and structures of 

 plants, and the study of these possibilities must be made 

 accessory to the consideration of the general principles of 

 plant life. What plants are and how and where they live are 

 the most fundamental questions, and are the ones which we 

 shall first consider in the following chapters. 



