FUNDAMENTAL NOTIONS 5 



9. Plant Geography. — The study of the present dis- 

 tribution of plants over the earth's surface, and of the 

 causes and consequences of this distribution, is plant 

 geography (sometimes called phytogeography) . 



10. Fossil Botany. — The oldest known rocks contain 

 the remains of plants that lived thousands — probably 

 millions- — of years ago. These remains often, though not 

 always, of stone, are fossils, and their study constitutes 

 the study of fossil botany, or paleobotany. This study 

 is not only interesting in itself, throwing much light 

 upon our knowledge of plants, but is also of great value 

 to the geologist, often helping him to interpret correctly 

 the rock -layer, and to decide to what geological age it 

 belongs. By means of fossils, we may also learn much 

 of the climate of past ages, and the great changes that 

 have since taken place. Thus, when we find fossil re- 

 mains of tropical plants, such as palms, in the rocks of 

 the present arctic regions, we know that there must have 

 been a tropical climate in that latitude at the time the 

 plants, now fossils, were living and growing there. 



11. Educational Value of Botany. — From the preced- 

 ing paragraphs it is evident that a study of plants will not 

 only give us valuable iriformation that may be used to 

 advantage in every day life, but that it will give us a 

 broader outlook than we might otherwise obtain over the 

 past and present of the world in which we live; it may 

 not only suggest' to us the vocation we would prefer to 

 follow, but may give us a breadth of view and a wealth 

 of ideas that will help to increase both our usefulness and 

 happiness. 



12. Plan of Study. — We shall first review the structure of 

 a familiar type of plant, and then make an elementary study 



