TROPICAL FLORAS 55 



MADAGASCAR (5000 species) 



1. Leguminosas . . 346 



2. Compositae . . 281 



3. Euphorbiaceae . . 228 



4. Orchideae . . 170 



5. Cyperaceae . . 160 



6. Rubiaceas . . 147 



7. Acanthaceae . . 131 



8. Gramineas . . 130 



Ferns . . 318 species. 



The above table was made when the whole flora consisted 

 of 3740 known species. As it is now increased to nearly 

 5000, the figures given will have to be increased by one- 

 third on the average. But as this increase may be very 

 unequal, they have been left as given. 



Flora of Tropical America 



We have seen reason to believe that the temperate flora 

 of North America is somewhat poorer than that of Europe 

 and northern Asia, though the south temperate zone as re- 

 presented by Chile is exceptionally rich. But there can be 

 little doubt that its whole tropical flora is extremely rich ; 

 and it may not improbably be found to contain nearly as 

 many species of plants as all the rest of the tropical world. 

 This may perhaps be indicated by the fact that it has 

 fourteen or fifteen natural orders quite peculiar to it, while 

 the remainder of the globe has about the same number ; 

 but, taking account of three other orders that are almost 

 exclusively American, Mr. Hemsley is of opinion that the 

 balance is on the side of America. 



America has the great advantage of possessing the largest 

 continuous or almost continuous extent of tropical forest on the 

 globe. The vast Amazonian plain forms its central mass of 

 about two millions of square miles of almost continuous forest. 

 From this there are northward extensions over the Guianas 

 and parts of Venezuela, along the north-east branch of the 

 Andes to Trinidad, and thence through Panama and 

 Honduras to the lowlands of eastern and western Mexico. 

 Southward it sends out numerous branches along the great 

 river valleys into central and western Brazil, and thence 

 along the eastern slopes of the Andes to beyond the 

 southern tropic ; while all along the Atlantic coast there is 

 a belt of equal luxuriance, spreading out again in the 

 extreme south of Brazil and Paraguay to about 30 of south 



