18 



a whole. Especially well developed groups in Borneo are the 

 Palmae, Araceae, Nepenthaceae, Melastomataceae, Dipterocar- 

 paceae, and Gesneraceae; in the Dipterocarpaceae and Nepen- 

 thaceae by far more species are known from Borneo than from 

 any other similar geographic area. 



The Bornean flora presents about forty-seven endemic 

 genera, in the total generic list of 1 152, but so far as our records 

 show a specific endemism of approximately 49 per cent. This 

 percentage of endemism is apparently about the same as that 

 of the Malay Peninsula, and will probably prove to be about the 

 same as that of Sumatra, but is doubtless higher than that of 

 Java; the Philippine flora apparently presents a somewhat higher 

 percentage of endemism, than does that of Borneo, my estimate 

 at this time being approximately 60 per cent. The study of the 

 endemism of Borneo and contiguous areas, such as the Malay 

 Peninsula and the Philippines emphasizes the fact that a high 

 degree of specific endemism is characteristic of each 

 geographically distinct region, and this will probably be found 

 to hold true for the entire Malayan region; and that each region 

 presents but a comparatively small number of endemic genera. 



The Bornean flora presents about 4924 species, distributed 

 into 1152 genera and 157 families so far as the Spermatophytes 

 are concerned, but as indicated above this number is probably 

 not more than fty per cent, of the species that actually occur 

 in Borneo. The vegetation of Sumatra and most other parts of 

 Malaya is so very imperfectly known that any conclusion drawn 

 regarding the alliances of the flora must of necessity be strictly 

 limited by our own ignorance. I am not in a position to discuss 

 in m.ore than very general terms the alliances of the Bornean 

 flora as presented by the following list, as while I have a fairly 

 intensive knowledge of the Philippine flora to the north-east, 

 my knowledge of that of the Malay Peninsula, Sumatra, and 

 Java is purely superficial. Any final conclusions must be based 

 on an immensely greater amount of data than is now available. 



/ It has long been known that the flora of Borneo is not 

 essentially different from that of the Malay Peninsula and the 

 other islands in the Sunda group, notably Sumatra and Java 

 and the contiguous smaller islands. Borneo naturally presents 

 what must be considered, at least in part, the center of distri- 

 bution of the typical Malayan flora. While it is certain that the 

 Malay Peninsula, Sumatra, Borneo, and Java formerly- 

 comprised a single land mass, as indicated by their relative 

 positions and the shallow seas separating them, yet they have 

 been separated for a sufficiently long time to allow for the 

 development of a high degree of endemism, not especially 

 noticeable so far as genera are concerned, but very evident in 

 regard to species, in each area. Unfortunately so little is known 



