RL'IWER 493 



been warranted by results obtained in Ceylon, where the tree has 

 ceased to be cultivated. 



Lagos Rubber. (Fiuitiuniti eltistica. Apocynaceie). A large, 

 upright tree, native of West tropical Africa, Uganda, etc., intro- 

 duced into Ceylon in 1897. Cultivation is much the same as for 

 Hevea, but, like Castilloa, an interval of 3 or 4 weeks must elapse 

 between each tapping; also like the latter, the latex takes a 

 comparatively long time to coagulate. An annual yield of one pound 

 or more per tree has been obtained from uncultivated trees in 

 Uganda, and the quality of the rubber is but little inferior to that of 

 Para rubber. The tree, however, takes longer than the latter to at- 

 tain a tappable size. In Ceylon, a caterpillar pest regularly attacks 

 and completely defoliates the branches. The seeds are small and 

 grain-like, with a long silky appendage at the top end; they retain 

 vitality well, and germinate readily in about fourteen days. 



Rambong, Assam or India Rubber. (Ficns clastica. Urtica- 

 ceae). A very large spreading tree, often with aerial roots developed 

 downwards from the branches, or with enormous buttressed roots 

 spread over the surface of the ground. The aerial or buttressed 

 roots as well as the stems may be tapped for rubber, but the tree 

 takes comparatively long to attain a tappable age; when at maturity, 

 however, it yields large quantities of good rubber. The tree does 

 not produce fertile seed in Ceylon, and has to be propagated by 

 cuttings, which do not strike root readily. 



Guayule, or Mexican Rubber (Parthcnium ' argentalum. Com- 

 positae). A small slow-growing shrub, 2 to 4 feet high, indigenous 

 to the deserts of Mexico. Of late years this came into pro- 

 minence as a source of a low-grade rubber. Besides what is 

 extracted locally, large quantities of the dried shrub have for 

 some time been exported to Germany and the United States for 

 the extraction of rubber, but the supply is limited and rapidly 

 diminishing, and, with the present low price of rubber, will pro- 

 bably soon cease. The plant cannot be cultivated with profit, as 

 it takes upwards of 20 years to come to maturity. In the process 

 of rubber extraction, the whole shrub is pulled up and crushed 

 between rollers. The plant contains no latex, but granules of 

 rubber are scattered throughout the tissues. At one time it was 

 cultivated in Malay, Java, etc., for rubber, but its cultivation has 

 now been discontinued. 



Ecanda, or Bitinga Rubber. (Raphionacnic utiJis. Asclepi- 

 adeae). A low stemless plant, bearing a large tuberous root, not 



