16 THE WORLD OF LIFE 



certainly surpass those of Africa, with three times their 

 tropical area, and may approach, though I do not think they 

 will equal, those of tropical America, or even of tropical 

 South America only. Portions of this area have been well 

 explored, especially the great peninsulas forming India 

 proper, Burma, and Indo-China ; but the two latter are only 

 sufficiently known to show their extreme richness botanically, 

 and the same may be said of the numerous large islands of 

 ^ the Malay Archipelago. We may, I think, be certain that 

 what is known of these two sub-regions is less than what re- 

 mains to be made known. 



Sir Joseph Hooker estimates the whole flora of British. 

 India at 17,000 species, including the desert flora of the Indus 

 valley and the rich temperate and alpine floras of the 

 Himalayas above an elevation of 6500 feet in the east and 

 above 4000 or 5000 in the west. But as I am here dealing 

 with tropical floras, it is only necessary for me to give such 

 figures as are available for the specially tropical portions of 

 it. 



The Indian Peninsula, bounded on the north by a curving 

 line of hills and mountains which run not far from the line 

 of the geographical tropic, is somewhat poor when compared 

 with the aboundino: riches of Burma and Indo-China; vet it 

 possesses areas, especially in the Western Ghats and the 

 Xiigiris, of great botanical richness and beauty, much of which 

 is still inadequately explored. Arid conditions prevail over 

 much of its surface, both in the north and in the central 

 plains, but these are interspersed w'ith deep moist valleys 

 containing a vegetation allied to that of Assam. As a result 

 of this greater aridity than that of the countries farther east, 

 the peninsula is much poorer in Orchids, having only 200 

 species against 700 in Burma ; but it has a great excess in 

 Grasses, L^mbellifer?e, Labiatj:Te, and Boragine?e, and a cor- 

 responding poverty in Melastomaceo?, Gesneracege, Myrtacese, 

 Palms, and other more peculiarly tropical orders. 



Ceylon, though so closely connected with the peninsula, has 



