176 OUTLINE OF PLANT GEOGRAPHY 



The Asiatic Tropics 



Unlike Africa, much the greater part of Asia is extratropical; 

 bul the southeastern part of the continent, Indo-China and Malaya, 

 shows a far more extensive and luxuriant tropical vegetation than 

 any part of Africa except the relatively small equatorial region of 

 the West Coast. The latter region, moreover, is much poorer in 

 species than the Indo-Malayan flora, whose only rival is equatorial 

 America. 



In western Asia, southern Arabia is the only region lying 

 within the tropics, and this, in climate and vegetation is closely 

 related to the regions on the African side of the Red Sea. Much of 

 tropical India is also arid or semi-arid, and it is only in limited 

 areas, like parts of the west coast, and the regions about the Bay 

 of Bengal, that the vegetation exhibits the luxuriant development 

 of the wet tropics, although owing to the mild climate of the south- 

 ern slopes of the Himalaya, the vegetation is largely composed 

 of tropical species which extend far into the temperate zone where 

 there is a mixture of tropical and boreal types. 



The tropical Asiatic forest attains its highest development in 

 the Malayan region, where equatorial conditions of heat and 

 moisture combine to produce a maximum growth of the rank, 

 exuberant, rain-forest vegetation. 



In the Malay Peninsula and the great islands of the Malay 

 archipelago, Borneo, Sumatra, Java, New Guinea, and the southern 

 Philippines, most of the lowland country has a hot-house climate 

 with almost constant temperatures, and very heavy and uniform 

 rainfall. When, in addition, rich volcanic or alluvial soils prevail, 

 as in western Java and parts of Sumatra, the luxuriance and 

 variety of the vegetation is unsurpassed in any part of the world. 



Arabia 



Arabia, north of the Tropic of Cancer, is in topography and 

 climate like the deserts of North Africa, and the vegetation is 

 much the same. The portion which lies within the tropics show 7 s 

 much variety of elevation, and a corresponding range in precipi- 

 tation and the resultant vegetation. 



From the almost rainless, intensely hot coastal belt along the 

 Red Sea and Indian Ocean, the southwest point of Arabia rises 



