INTRODUCTION. 



the objects of our study, by being acquainted with their dif- 

 ferent names and representatives among writers, and where 

 every new step must be accomplished by a comparison of all 

 earlier observations. 



2. The Geography of Plants, or the examination of the 

 causes which determine plants to choose certain regions and 

 stations. This knowledge respecting the distribution of plants 

 is naturally enough included under the second great depart- 

 ment, or that which relates to the Physiology of plants. It 

 has of late begun to be studied with particular zeal, and is 

 fitted to afford the most important assistance in the Classifi' 

 cation of plants. 



3. The knowledge of the Anomalies to which the forms of 

 the Vegetable Kingdom are subject ; to which belongs also 

 the doctrine of the Malformation and Diseases of plants. If 

 we consider these variations in their most comprehensive rela- 

 tions, their study is one of the most difficult, but it is also 

 one of the most instructive parts of Botany. The doctrine of 

 the diseases in particular, is called the Pathology of Plants. 



4. The applications of these different parts of knowledge to 

 the arts and business of life are excluded from this Treatise ; 

 yet it cannot be denied, that these applications often reflect 

 an important light upon the science itself. The knowledge of 

 the officinal plants has been called Medical Botany ; the 

 knowledge of the plants which are employed in agriculture 

 and husbandry, is called (Economical Botany ; that of the 

 plants which are useful in arts and trades, is called Technical 

 Botany ; and the knowledge of forest trees, is the Botany of 

 Forests. 



4. 



All these different branches of the science, or parts of Bo- 

 tany, are connected together in the closest manner. They 

 cannot well be treated or learned separately, Avithout disadvan- 

 tage to the science ; and one chief cause of the interruptions 

 which are given to the progress of Botany, lies in the separa- 

 tion of these individual branches. 



A 3 



