TROPICAL FLOEAS 59 



Madagascar (5000 species) 



1. Leguminosae 346 



2. Compositae 281 



3. Euphorbiaceae 228 



4. Orchideae 170 



Ferns 



5. Cyperaceae 160 



6. Rubiaceaj 147 



7. Acantluiceae 131 



8. Giamineae 130 



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 sriven. 





Flora of Tropical America 



We have seen reason to believe that the temj^erate flora of 

 ^orth America is somewhat poorer than that of Europe and 

 northern Asia, though the south temperate zone as represented 

 by Chili 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 per- 

 haps be indicated by the fact that it has fourteen or fifteen 

 natural orders quite peculiar to it, wdiile 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 



