SUBJECTS TREATED IN THIS BOOK 3 



prepares the way for others. On exposed rocks only very small 

 plants are able to grow at first, but due to their presence soil 

 accumulates and larger plants are able to follow. Such problems 

 as the above are studied in Ecology. Ecology studies plants in 

 relation to the effects of soil, climate, and friendly, or hostile 

 animals and plants. It also studies the effect of the different 

 conditions upon the form and structure of plants. 



Plant Geography is much like Ecology and treats of the dis- 

 tribution of the different kinds of plants over the earth's surface. 

 Taxonomy, or Systematic Botany, treats of the classification 

 of plants. As a result of this kind of study, plants have been 

 arranged in groups, such as Algae, Bacteria, Fungi, Mosses, 

 Ferns, and Seed Plants. These large groups are further sub- 

 divided into smaller groups. Keys have been arranged by which 

 plants unknown to the student may be identified. Through the 

 study of Systematic Botany one can learn the names and some 

 of the characteristics of the different kinds of Grasses, weeds, 

 shrubs, and trees that grow on the farm or in any other region. 

 Economic Botany treats of the uses of plants to man. 

 Paleobotany is concerned with the history of plants as shown 

 by their preserved forms, known as fossils, which occur in the 

 different layers of rock composing the earth's crust. Paleobotany 

 is studied in connection with Geology. In the study of this 

 subject much has been learned about the plants which lived 

 millions of years ago, and this knowledge is very useful in under- 

 standing the evolution of the plants which now exist. 



Subjects treated in this Book. — ■ To become a master in any 

 one of the above subjects would require years of one's time. A 

 study of any of the special subjects of Botany requires a general 

 knowledge of the anatomy and the functions of plant struc- 

 tures This means that one must have a general course in 

 Botany before making a special study of Morphology, Plant 

 Physiology, or any of the special botanical subjects. One 

 purpose of this book is to give a general knowledge of cultivated 

 plants, of plants not cultivated but like the Rusts and Smuts 

 related to Agriculture, and of those plants which one must 

 know in order to understand the evolution of plants. Another 

 purpose is to give such a general knowledge of plant anatomy 

 and the functions of plant structures, that one will have the 

 necessary knowledge for the study of such agricultural subjects 



