BOTANY 



on the surface of the earth and to elucidate the causes of this. 

 Extinct plants and the succession of plants in time form the subject 

 matter of PALAEOPHYTOLOGY, which is thus the historical study of the 

 changes which have taken place in the vegetation of the earth. All 

 these are subdivisions of PURE or THEORETICAL botany. 



Botany does not, however, pursue theoretical aims only ; it is also 

 concerned with rendering the knowledge so obtained useful to 

 mankind. For instance, accurate information is obtained regarding 

 plants of economic value and how to better employ these, and 

 adulterations of substances of vegetable origin are detected. There 

 have thus to be added to the divisions of pure botany the numerous 

 branches of APPLIED BOTANY, e.g. the study of medicinal plants and 

 drugs, of vegetable food-substances, of technically valuable plants and 

 their products, agricultural botany, and that part of plant pathology 

 which is concerned with the prevention and treatment of diseases of 

 plants. 



In this work, which is primarily concerned with pure botany, a 

 division is made into a general and a. special part. The object of 

 GENERAL BOTANY is, by well-devised experiments and by comparison, 

 to ascertain the most distinctive properties of plants in general or of 

 the main groups. General botany is further divided into the two 

 sections treating of morphology and physiology. 



The object of SPECIAL BOTANY is to describe the structural 

 features, the methods of reproduction, and the modes of life of the 

 various groups of plants. It attempts also to express the more or less 

 close relationships which exist between plants by arranging them in 

 as " natural " a system as possible. In this special part a few main 

 facts as to some branches of applied botany, especially regarding 

 pharmaceutical plants, are inserted. The results of palaeophytological 

 study are placed in relation to the description of the particular groups 

 of existing plants. Lastly, the geography of plants is touched on, 

 though no connected account of it is attempted. 



