INIJIA RUBBEK OR CAOUTCHOUC. 23 



been attached to the sources of rubbers or caoutcboucs from 

 the East. From specimens brought to Kew, however, in 

 1880, it would seem that all the rubber from the Malay 

 Peninsula is furnished by species of Willughbeia and Leu- 

 conoiis, allied genera belonging to the natural order Apocy- 

 nacese, to which the Landolpliias before mentioned as the 

 sources of African rubber belong. The following species of 

 WUlughbeia have been referred to in the " Kew Report " 

 for 1880 as the probable source of the Malayan rubbers ; — 



1. Willughbeia Burbidgei, nov. sp., known as Manungan 

 pulau. 



2. W. Treacheri, nov. sp., known as Bertabu, and 

 probably the source of the rubber of North- West Borneo. 



3. Leuconotis eugeni/olius, known as Manungan bujok, 

 which is said to yield the best gutta (or rubber) of the 

 Bornean woods. 



4. Ghilocarpus viridis, also a Borneaii species of Apocy- 

 naceee yielding caoutchouc. 



5. Ghilocarpus Jlavescens, nov. sp. Of this, excellent 

 specimens were received at Kew in 1880 from the Singapore 

 Botanical Gardens. The quality of the rubber from this 

 plant was reported upon by Mr. Silver as " very fair " and 

 "useful in our manufactures.'' It was valued at the time 

 at Is. 3d. a pound. 



From the great attention that rubber-yielding plants 

 have received at Kew during the past few years, it would 

 seem to be proved that what is known in commerce as 

 Borneo rubber is not yielded by Urceola elasttca, as has 

 been generally stated in all works hitherto dealing with the 

 subject, but by one of the plants here mentioned, or at 

 least by some allied species. 



Fiji Rubber [Alstonia plumosa). — A sample of this was 

 first sent to Kew in 1877 by Sir Arthur Gordon, the then 

 Governor. It was favourably reported upon as a " strong, 

 elastic, pure rubber of the same character as the higher 



