20 



ignorance of the Bornean flora as a whole, as well as our very 

 imperfect knowledge of the vegetation of some of the 

 surrounding regions. Thus species reported only from the 

 Malay Peninsula and Borneo approximate 300, while those 

 known only from Java and Borneo are but about 110. While we 

 might infer from this that the Bornean flora is more closely 

 allied to that of the Malay Peninsula than to that of Java, yet 

 I suspect that the explanation of the difference between the two 

 lists lies largely in the fact that Borneo-Malay Peninsula 

 material has been much more compared in working up the flora 

 of the latter region than has Borneo-Java material in the work 

 done on the Javan flora. 



I have already indicated that the Sumatran flora is too 

 little known to warrant drawing any definite conclusions 

 regarding the relationships between the floras of Sumatra and 

 Borneo. The indications are that the floras of these two large 

 islands closely resemble each other as would be expected from 

 their relative positions, the shallow sea separating them, and 

 the intervening islands of Banca and Billiton. About 98 species 

 are reported only from Sumatra and Borneo, but very few genera 

 have this limited distribution. 



It is interesting to note that about 135 species are reported 

 from but not beyond the Malay Peninsula, Sumatra and Borneo, 

 emphasizing the fact that these regions present much in common 

 so far as their flora is concerned, and indicating their former 

 union in one land mass in past geologic times; a number of 

 genera are confined to these three regions. A similar list could 

 be compiled of those species known from the three regions 

 mentioned and Java; and from the Malay Peninsula, Borneo, and 

 Java; but most of those species now reported from the Malay 

 Peninsula-Borneo-Java are almost certain to occur in Sumatra, 

 as are those reported only from Java-Sumatra, or J^va-Malay 

 Peninsula, or even Malay Peninsula-Sumatra, to occur in 

 Borneo. 



From the geographic position of the Philippines to the 

 north-east of Borneo and with two definite lines of connecting 

 islands between Borneo and the Philippines, the Sulu 

 Archipelago to the south and the Palawan-Calamianes-Mindoro 

 groups to the north, we might logically infer that much of our 

 present Philippine flora had been derived from Borneo through 

 previously existing land-connections. In the known geographic 

 distribution of a few species, Malay Peninsula-Borneo-Philip- 

 pines, and Malay Peninsula-Sumatra-Borneo-Philippines it is 

 perhaps evident that there has been a certain part of the 

 Philippine flora derived from this source. However, the 

 list of species with the limited geographic distribution of 

 Borneo-Philippines is comparatively small, about 60 and a 



