The Philippine 

 Journal of Science 



Vol. 23 JULY, 1923 No. 1 



DISTRIBUTION OF THE DIPTEROCARPACEAE 



ORIGIN AND RELATIONSHIPS OF THE PHILIPPINE FLORA AND CAUSES 



OF THE DIFFERENCES BETWEEN THE FLORAS OF 



EASTERN AND WESTERN MALAYSIA 



By Elmer D. Merrill 

 Director and Botanist, Bureau of Science, Manila 



In discussing the biological differences between eastern and 

 western Malaysia, and in attempting to explain the reasons 

 for the manifest differences between these two regions, various 

 authors have considered the mammals, birds, reptiles, batra- 

 chians, mollusks, fresh-water fishes, and insects with or without 

 reference to the geology, paleontology, hydrography, and cli- 

 mate of the entire region. It has long been known that there 

 are striking differences between the floras of eastern and western 

 Malaysia, but hitherto no direct comparison seems to have been 

 made between them. How significant these differences are is 

 strikingly brought out on page 24. 



In this paper the term Malaysia is used to define the entire 

 region from the Malay Peninsula to New Guinea, including the 

 Philippines. Western Malaysia includes the Sunda Islands and 

 the Malay Peninsula, that is, Sunda Land of Molengraaff; 

 eastern Malaysia includes all the "Islands east of the Macassar 

 Strait, including New Guinea. For purposes of discussion the 

 Philippine Archipelago is considered as an independent area. 



In discussing zoogeographic alliances one fact that must not 

 be overlooked is that, before any considerable fauna can exist 

 in any region, the vegetation must be present. In other words, 



