334 



Of the unidentified speeies two give respectively a red and white 

 rubber apparently valuable, the remainder an inferior or practically 

 valueless sticky rubber. These jungle rubbers are it seems very 

 abundant in many parts of the region and the rubber is collected 

 by the natives. It is not collected as a rule in the wet season. The 

 amount obtained in a single day by a man is estimated by two ob- 

 servers as one kilogramme (2 lbs. 3 ozs.) and by others very much 

 less from 90 to 100 grammes (1,500 grains). A vine about .10 metre 

 (3! inches) in diameter at the base gives 200 grammes a year. As 

 is done in the Malay Peninsula, the natives where they find a variety 

 of rubber vines, mix the rubber obtained. 



The seeds of Ecdysanthera, and one of the unidentified species 

 collected at the end of the dry season took about 2 months to ger- 

 minate. The seeds should not be covered with soil more than just 

 enough to prevent their being washed away by watering or heavy 

 rain. They require a fair amount of shade, plants unsufficiently 

 protected from the sun being killed. M. Achard however prefers 

 propagating these rubber vines by cuttings, and states that the best 

 results were obtained with stems a little thicker than a pencil. 

 Marcottage gave good results but was too troublesome. The 

 growth is said to be rapid and they attain their full growth in six 

 or seven years. 



The discovery of any additional rubber producing plants in any 

 part of the world is always interesting, even although their value 

 may not be very great. It is noticeable that none of these new 

 rubber vines as far as identified belong to the genera Willughbeia 

 or Urceola, which have supplied the best rubbers of the Asiatic 

 forests, but to genera which as rubber producers (Parameria ex- 

 cepted) have been quite neglected. The cultivation of rubber vines 

 on a large and profitable scale still offers many difficulties. Many 

 though attaining a large size in the forests, seem to grow slowly 

 and make stems so slender that it is very difficult to see how to 

 extract the rubber except at a prohibitive cost. The methods of 

 extraction from the dry bark may eventually help to solve the diffi- 

 culty, but the main crux at present is to get the plants to produce 

 large enough stems to be worth the expense of barking. At pre- 

 sent the rubber-vines which seem under open cultivation to produce 

 the largest stems are the Landolphias of which several species are 

 very stout and strong growers. The plan of growing these vines 

 in forest more or less thinned is expensive the plants with the 

 forest occupying a large area, and also requiring a great deal of 

 thinning and weeding work. A tree to carry the weight of a really 

 large sized Willughbeia must be of large size and is very liable 

 when the vine has attained full size or is approaching it to be 

 strangled, or smothered by the vine itself. The rapidity of growth 

 of a rubber vine under these conditions is not yet determined, and 

 it appears that in many cases where it has been approximately de- 

 termined it has been very much over rated. Much depends on the 

 amount of light in the forest, and the absence of under growth 

 which would crowd out the young vines, and this in most tropical 

 forests would entail a considerable amount of constant labour. 



