76 ECONOMIC CONDITIONS ( No. 99 ( Landolphia ), but some from trees ( Funtumia ). A con siderable quantity is obtained from the so -called ' grass or root rubbers ' , aberrant Landolphias of the grass uplands of the southern Kasai plateau. Originally forest climbers, but now growing in a region long denuded of its forest, these Landolphias creep at a level of a few inches beneath the soil for 80 or 100 ft., throwing up each rainy season a tuft of small branches bearing leaves, flowers, and fruit. The rubber is con tained in the bark of these subterranean lianes or rhizomes, which are first sun-dried, then beaten to loosen the bark. This is then beaten until the small pieces of rubber can be picked out of the resulting débris. The most valuable of the several species is Landolphia thollonii.

Supplies of wild rubber in the Congo are still almost unlimited , but after 1910, owing to the withdrawal of the Government monopoly and the drop in prices on the European markets, the natives ceased to interest themselves in its collection , and the industry declined by nearly two -thirds. In 1913 the freight charges on river steamers and railways were therefore reduced by about 50 per cent. , in order to stimulate export.

As regards plantation rubber, Hevea brasiliensis, a South American species, grows and yields well, but as it is expensive to cultivate and needs skilled labour and machinery, it is not likely that Pará rubber will ever bulk largely in the rubber exports of the Congo.

Funtumia elastica , the indigenous rubber-tree of tropical Africa, might with great advantage be planted over wide areas of forest land in some districts, where the red laterite soil, in which this tree flourishes, is to be found. It requires special planting methods, which are well understood by the natives. No skill is required for the tapping, and the rubber, which is of high quality, need not be prepared by machinery.