26 OUTLINES OF FORESTRY. 



There, therefore, will be found in every section 

 of country a plant growth or plant life peculiar 

 to, or naturally belonging to, such a section of 

 country. Each section of country possesses, so 

 to speak, a nationality in its plants, or, in other 

 words, there lives in each section of country a 

 particular nation of plants. Such a nation of 

 plants, or the plants peculiar to a particular sec- 

 tion of country, is called its flora. 



Since heat, light, and moisture are, next to the 

 presence of the plant germ, the most important 

 things for plant growth, there will necessarily 

 exist in different parts of the earth a flora that will 

 vary according to the differences that exist in the, 

 distribution of heat, light, and moisture over such 

 part of the earth's surface. 



The heat, light, and moisture are greater in 

 amount at the equator than at any other portion 

 of the earth's surface. Therefore, the vegetation 

 is more luxuriant, or possesses a greater diversity 

 of forms, here than at any other part of the sur- 

 face. As we pass from the equator towards the 

 poles, the decrease in the heat, light, and moisture 

 causes a corresponding decrease in the variety and 

 luxuriance of vegetable life. 



In passing from the base to the summit of a 



