PART 11. 



SYSTEMATIC BOTANY, TAXONOMY, OR THE 

 CLASSIFICATION OF PLANTS. 



CHAPTER I. 



SYSTEMS OF CLASSIFICATION. 



This department of Botany may be considered as a combination of all 

 the observations made on the structure and physiology of plants, with 

 the view of forming a scientific arrangement. It can only, there- 

 fore, be prosecuted successfully after the student has acquired a com- 

 plete knowledge of Organography. In every branch of science 

 arrangement is necessary in order that the facts may be rendered 

 available, and this is more especially the case when a knowledge of 

 species is to be acquired. When it is considered that there are up- 

 wards of 150,000 known species of plants, it is obvious that there 

 must be a definite nomenclature and classification, were it only to , 

 facilitate reference and communication. Taxonomy has sometimes 

 been pursued with no higher aim than that of knowing the names of 

 plants. When prosecuted in such a spirit, it does not lead to an en- 

 larged and philosophical view of the vegetable kingdom. In all truly 

 scientific systems regard is paid not merely to the determination of 

 the names of the species, but to their relations and afiBnities, so as to 

 give some conception of the order which has been followed in the 

 plan of creation. 



In Classifactory Sciences the arrangements are founded upon an 

 idea of liJcmess — an idea, however, which is applied in a more exact 

 and rigorous manner than in its common and popular employment. 

 The resemblances of the objects must rest not on vague generalities, 

 but upon an accurate scientific basis. In order that an arrangement 

 may be constructed on philosophical principles, and that it may be 

 rendered useful for the purpose of science, the following steps are re- 

 quired : — 1. A Technical {Ts^vmog, artistic) language, rigorously de- 



