BOTANY. 



PART I. 



VEGETABLE ANATOMY, OKGANOGRAPHY, AND 

 PHYSIOLOGY. 



1. BOTANY is that branch of science which comprehends the know- 

 ledge of all that relates to the Vegetable Kingdom. It embraces a con- 

 sideration of the external configuration of plants, their structure, the 

 functions which they perform, the relations which they bear to each 

 other, and the uses to which they are subservient. It has been 

 divided into the following departments : 1. Structural Botany, or 

 Organography, which has reference to the textures of which plants are 

 composed, and to the forms of their various organs. 2. Physiological 

 Botany, in which plants are considered in their living or active, state, 

 and while performing certain vital functions. 3. Systematical Botany, 

 or Taxonomy, the arrangement and classification of plants. 4. Geogra- 

 phical Botany, or the distribution of plants over the globe. And, 5. 

 Fossil Botany, or the nature of the plants found in a fossil state in the 

 various geological formations. 





CHAPTER I. 

 ELEMENTARY ORGANS, OR VEGETABLE TISSUES. 



2. In their earnest and simplest state, plants consist of minute vesicles, 

 formed by an elastic transparent membrane, which is composed of a 

 substance called Cellulose. This substance is of general occurrence, 



B 



