INTRODUCTION. 



With these two is conveniently associated the Terminology, or 

 technical language of Botany. 



III. Physiology : the study of vital phenomena, or of those pro- 

 cesses and actions performed by the living plant, including those 

 specially characteristic of plants, and also those which are com- 

 mon to the animal kingdom, as well as the consideration of the 

 general physical agencies pertaining to the mineral kingdom equally 

 with the two others. 



IV. Classification, which is the study of the mode of arranging 

 the kinds of plants in groups and series of groups either " artifi- 

 cially,''' when convenience and facility of study are the chief aims, 

 or according to their supposed lineage and kinship, and thus to ex- 

 press in an abstract form their mutual relations and their degrees 

 of perfection in organization. This department includes the 

 Principles of Descriptive Botany and of the Nomenclature of kinds 

 and classes of plants. 



Applied Botany is divisible into many departments. That most 

 closely connected with Philosophical Botany is Descriptive Botany, 

 which is the art of describing the particular kinds of plants in 

 technical language, in such a manner that they may be readiJy re- 

 cognized by botanists. Special works are commonly devoted to 

 this branch, and are very commonly confined to the plants of a 

 limited area, as a particular country or even province ; such books 

 are called Floras. Pharmaceutical Botany treats of the medicinal, 

 nutritious, or poisonous properties of plants. Vegetables posses- 

 sing such properties are generally included under the head of 

 Materia Medica, to which subject special treatises are also devoted. 

 Agricultural, Horticultural, and Economic Botany are often treated 

 as distinct subjects : the first two are founded on the application 

 of the principles of Physiological Botany ; the last on the ascer- 

 tained facts of Comparative and Elementary Anatomy, and on the 

 combination of these facts with chemical and mechanical knowledge. 



None of these departments of Applied Botany receive separate treat- 

 ment in this work, although incidental reference is made to them to 

 indicate the application of the laws and facts of Philosophical Botany 

 to them. 



Botanical Geography and Botanical Geology (or Paleontology) 

 are mixed studies, founded on the association of the results of pure 

 and of applied Botany \\ ith those of other sciences : the first is re- 

 lated most closely to Physiological Botany, but has some problems 

 sui generis, to be solved only by independent facts and observa- 

 tions; the second has some very interesting relations with the 

 Scientific Classification of plants. These two departments, as 

 applications of the science, have a peculiar philosophical interest, 

 but can only be very briefly alluded to in this volume. 



