20 INTRODUCTION 



while many animals, like the sponge, are stationary in the 

 adult condition. Fungi, although plants, have no chlorophyll. 



Every distinction between the lower plants and animals 

 may disappear except that of the presence or absence of 

 chlorophyll and the modes of nutrition. Animals take food 

 in the solid form while plants take food in the liquid and 

 gaseous form. All plants and animals have been derived 

 from a unicellular ancestor. The presence of chlorophyll 

 enables plants to manufacture food without moving from 

 place to place; therefore, they do not need a muscular and a 

 nervous system. Animals have no chlorophyll] they have 

 developed, therefore, a muscular and a nervous system in 

 order that they may move from place to place to secure 

 food. 



When we study plants and animals we are studying biology. 



Biology including Zoology and Botany is the science of 

 living things. 



The word botany is derived from a Greek word for " herb- 

 age," from "bosco" meaning "to graze." Botany is the 

 science of plants. 



At the present time botany has many subdivisions, of 

 which the most important are the following : 



Plant Taxonomy or Systematic Botany is the study of 

 plants for the purpose of determining their relationship. 



Plant Morphology is the study of the structure and form 

 of plants. 



Plant Physiology is the study of the functions of the differ- 

 ent organs of the plant. 



Plant Geography or Geographical Botany is the study of 

 the distribution of plants over the earth's surface. 



Plant Ecology is the study of the relation of plants to the 

 conditions under which they grow. 



