INTRODUCTION. 15 



of species, all constructed upon one general plan, indeed, but this 

 plan modified in each according to the rank it holds, and the cir- 

 cumstances in which it is placed. This leads to the second great 

 department of the science, namely, SYSTEMATIC BOTANY, or 

 the study of plants in their relations to one another; as forming a 

 vegetable kingdom, which embraces an immense number of species, 

 resembling each other in very various degrees, and therefore capable 

 of being grouped into kinds or genera, into orders, classes, &c. 



6. Thus arises Classification, or the arrangement of plants in 

 systematic order, so as to show their relationships ; also Special 

 Descriptive Botany, embracing a scientific account of all known 

 plants, designated by proper names, and distinguished by clear and 

 exact descriptions. Necessarily connected with these departments 

 is Terminology or Glossology, which relates to the application 

 of distinctive names or terms to the several organs of plants, and 

 to their numberless modifications of form, &c. The accomplishment 

 of this object renders necessary a copious vocabulary of technical 

 terms ; for the current words of ordinary language are not suf- 

 ficiently numerous or precise for this purpose. New terms are 

 therefore introduced, for accurately expressing the great variety 

 of new ideas to which the exact comparison of plants gives rise ; 

 and thus a technical language has gradually been formed (in this 

 as in every other science), by which the botanist is able to describe 

 the objects of his study with a clearness and brevity not otherwise 

 attainable. 



7. These several departments include the whole natural history 

 of the vegetable kingdom, considered independently. But, under 

 a third point of view, plants may be contemplated in respect to their 

 relations to other parts of the creation ; whence arises a series of 

 interesting inquiries, which variously connect the science of Botany 

 with Chemistry, Geology, Physical Geography, &c. Thus, the re- 

 lations of vegetables with the mineral kingdom, considered as to 

 their influence upon the soil and the air, — as to what vegetation 

 draws from the soil and what it imparts to it, what it takes from 

 and what it renders to the air we breathe ; and, again, the relations 

 of the vegetable to the animal kingdom, considered as furnishing 

 sustenance to the latter, and the mutual subservience of plants and 

 animals in the general economy of the world, — all these inquiries 

 belong partly to Chemistry and partly to Vegetable Physiology ; 

 while the practical deductions from them lay the foundation of 



