12 INTRODUCTION. 



18. Botany is the science of the vegetable kingdom. It in- 

 cludes the knowledge of the forms, organs, structure, growth, 

 and uses of plants, together with their history and classification. 

 Its several departments correspond to the various subjects to 

 which they relate. Thus, 



19. Structural Botany, or Organography, treats of the special 

 organs of plants as compared with each other, answering to 

 Comparative Anatomy in the science of Zoology. Morphology 

 is a term often used in a similar sense ; but it especially relates 

 to the mutual or typical transformations which the organs un- 

 dergo in the course of development. 



20. Elementary Botany treats of the elementary tissues the 

 organic elements out of which the vegetable fabric is constructed. 



21. Physiological Botany is that department which relates to 

 the vital action of the several organs and tissues, including both 

 the vital and chemical phenomena in the germination, growth, 

 and reproduction of plants. It has, therefore, a direct and prac- 

 tical bearing upon the labors of husbandry in the propagation 

 and culture of plants, both in the garden and in the field. 



22. Systematic Botany arises from the consideration of plants 

 in relation to each other. It aims to arrange and classify plants 

 into groups and families, according to their mutual affinities 

 and relative rank, so as to constitute of them all one unbroken 

 series or system. 



23. Descriptive Botany, or Phytology, is the art of expressing 

 the distinctive characters of species and groups of plants with 

 accuracy and precision, in order to their complete recognition. 

 A Flora is a descriptive work of this kind, embracing the plants 

 of some particular country or district. 



24. Finally, in its extended sense, Botany comprehends also the knowledge of the rela- 

 tions of plants to the other departments of nature particularly to mankind. The ulti- 

 mate aim of its researches is the development of the boundless resources of the vegetable 

 kingdom, for our sustenance and protection as well as education : for the healing of our 

 diseases and the alleviation of our wants and woes. This branch of botanical science is 

 called Applied Botany, including several departments as Medical Botany, or Pharmacy ; 

 Agricultural Botany, or Chemistry ; Pomology, etc. 



25. The name of a plant or other natural object is twofold, 

 the trivial or popular name, by which it is generally known in 

 the country; and the Latin name, by which it is accurately 



