24 The Philippine Journal of Science m» 



Malaysia. Of these nine Isoptera is known only from the Malay 

 Peninsula, Bangka, Borneo, and Mindanao ; Parashorea is known 

 only from the Malay Peninsula, Sumatra, Borneo, and the Phil- 

 ippines (Luzon to Mindanao) ; and Pentacme is known only from 

 the Malay Peninsula and the Philippines (Luzon to Mindanao) . 



It has long been known that there are striking differences 

 between the floras of eastern and western Malaysia, but it 

 seems that as yet no botanist has made a direct comparison to 

 see wherein the differences lie. The number of species is so 

 great (estimated by me at 45,000 for the entire region, includ- 

 ing the Philippines) that I have been obliged to limit my inves- 

 tigations to a larger unit and have selected the genus as the 

 unit. This task has been sufficiently arduous, for the number 

 of genera involved is approximately 3,000. 



In comparing the ranges of all genera of flowering plants 

 known from the Malaysian region as between eastern and west- 

 ern Malaysia and the Philippines, eliminating those introduced by 

 man in modern times, we note the following significant results : 

 In western Malaysia we find about three hundred fifty-six genera 

 which are not known from east of Wallace's Line, but in the 

 Philippines two hundred eighteen, or 61 per cent, of these occur. 

 In eastern Malaysia we find about two hundred twenty-five 

 genera which do not extend to western Malaysia, and of these 

 fifty -six, or about 25 per cent, are known from the Philippines. 



We have then in the Philippines numerous genera from west- 

 ern Malaysia that do not occur in eastern Malaysia, and fewer, 

 but at the same time a most striking assemblage, of Celebesian, 

 Moluccan, Papuan, and Australian types that extend to the 

 Philippines but do not reach western Malaysia. There are 

 Australian types in western Malaysia, but few indeed as 

 compared with the same element in the Philippine flora. In 

 general, then, the generic distribution in Malaysia confirms the 

 conclusions that may be drawn from the study of the distri- 

 bution of the Dipterocarpaceae, namely: That there were certain 

 definite land connections between Borneo and the Philippines 

 over which the western Malaysian elements migrated into the 

 Philippines, including our Dipterocarpaceae, numerous genera 

 of wide Malaysian distribution, and the two hundred eighteen 

 genera that occur in western Malaysia and the Philippines but 

 not in eastern Malaysia. Later these connections were broken, 

 between Mindoro and the Calamian Islands to the north and 

 in the Sulu Archipelago to the south, inhibiting further Bornean 

 migrations into the Archipelago proper but permitting later 



