22 THE WOKLD OF LIFE 



This is used in many different ways. In one the minimum 

 number of orders whose species added together form one-half 

 of the whole flora are given. Thus, it was found that in the 

 Province of Bahia (Brazil) the 11 largest natural orders com- 

 prise half the whole number of species. In British Guiana 

 12 orders are required, and in British India 17. Coming to 

 temperate regions, in Japan there are 16, in Europe 10, in 

 Sweden 9, in Iceland and in Central Spain 8. The general 

 result seems to be that those regions which are very rich in their 

 total number of plants require a larger number of their pre- 

 ponderant orders to make up half the total flora ; which implies 

 that they have a larger proportion of orders which are approxi- 

 mately equal in number of species. 



Another mode of comparison is to give the names of the 

 first three or four, or even ten or twelve, of the orders which 

 have the greatest number of species. It is found, for example, 

 that in equatorial regions LeguminossB usually come first, 

 though sometimes Orchids are most abundant ; in temperate 

 regions the Composites or the Grasses; and in the Arctic, 

 Grasses, followed by Crucifera? and Saxifrages. A few of the 

 tables constructed by De Candolle are given as examples. 



British Guiaxa ( Scliomburgh ) 



3254 species 



Leguminosae 469 species 



Orchidese 214 " 



Rubiacege 176 " 



Melastomaceae 126 " 



The Andes of New Grenada (Humboldt) 



1041 species 



Composite 86 species 



Leguminosae 65 " ' 



Rubiacese 49 " 



Graminese 42 " 



Orchidese .it,,. • 41 " 



