406 FOREST PRODUCTS 



Oca (Cerv.} which grows principally in Guatemala, Nicaragua, Southern 

 Mexico and in northern South America west of the Andes. The same 

 general method of collecting and treating the latex as described for the 

 Hevea is followed, although there are many variations. 



3. Guayule is the trade name applied to rubber from Partheninm 

 argentatum from Mexico, which has entered the rubber markets in a 

 prominent way during the past decade. It does not command the high 

 price which Para rubber does. 



4. The principal rubber plant of the African tropics is the Funtumia 

 elastica, called " Africans " or " logos " in the trade. The rubber is of 

 excellent quality, but it generally contains considerable impurities. 



5. The climbing vines of Africa have entered prominently in the 

 rubber trade, especially in Sudan, Congo and Mozambique. The vines 

 are generally destroyed in the process of collecting the latex. They 

 consist largely of several species of Landolphia, especially L. owariensis. 

 The Kickxia elastica is also closely associated in this group and enters 

 the trade under the name of " Africans." 



6. The rubber tree commonly planted as an ornamental tree is the 

 Ficus elastica, which produces the Assam or Rambong rubber of com- 

 merce, which is known in the American rubber trade as " East Indian." 

 It attains a large size in Ceylon, India and Malaysia. Owing to the crude 

 methods of collection it does not command a very high price. It fur- 

 nishes much of the native wild rubber of India, Sumatra and Java. 



7. Jelutong or Pontianak is the name of an East Indian rubber 

 derived Dyera costulata. 



8. The manihots or " manicobas," which is the common trade name, 

 come largely from Manihot glaziovii, a native of Brazil, and a close rela- 

 tive of the tapioca plant. It grows at elevations up to 4000 ft. along the 

 Andes Mountains. 



9. Mangabeira is the trade name of the rubber derived from Han- 

 cornia speciosa, a native tree of Brazil. It is also called Pernambuco 

 rubber. 



10. Balata is the rubber from Mimusops balata, which grows in Brit- 

 ish and French Guiana. 



11. Gutta percha is largely derived from a species called Palaquium 

 gutta. Inferior guttas called gutta siak are secured from several species. 



Many other plants yield a latex or rubber-bearing fluid and it is 

 said that large forests of rubber plants are still undeveloped owing to their 

 inaccessibility in the remoter districts of the tropics. However, the 

 above represent practically all that are of present commercial importance. 



