LATEX-PRODUCING PLANTS 365 



tation of African rubber. African natives are said to be the world's 

 worst rubber collectors, and seem incapable of learning better 

 methods. There are three leading kinds of African rubber, one 

 of which may come to be of some economic interest, if properly 

 developed. 



Landolfia rubber comes from several African woody vines 

 of the Dogbane Family. These yield a latex which is coagulated 

 by plant juices, by heat from the sun, or from native bodies on 

 which it is often smeared for coagulation. The plants are cut 

 down, chopped into pieces, and the latex allowed to exude and 

 coagulate as described above. The climbing habit of this plant 

 precludes its use in plantations; in its native habitat it reaches 

 the tops of the tall jungle trees by means of hook- tendrils, much 

 like wild grapes of our temperate regions. 



Lagos rubber comes from a large tree of tropical west Africa, 

 also of the Dogbane Family. Undiscovered until 1894, it was 

 then exploited so wastefully that near extermination followed 

 its discovery. It is now being cultivated in Africa, but is not 

 competing seriously with Para rubber plantations in the same 

 area. At the time of discovery, the Lagos rubber tree was plenti- 

 ful, but trees were either felled or tapped to such heights that 

 they were killed. The extracted latex is hardened by boiling, 

 the bark is then peeled and macerated, and the remaining rubber 

 is worked into balls. 



Intisy rubber comes from an almost leafless, cactus-like 

 plant of the Spurge Family, inhabiting desert regions of Mada- 

 gascar, which at one time supplied a considerable amount of 

 rubber. Intisy, like other African rubber-producing plants, was 

 almost rendered extinct by destructive exploitation. The latex 

 exudes and hardens into strands on the surfaces of the plant, 

 from which it is removed and rolled into balls of high grade, 

 elastic, rubber. This plant, along with several rubber-yielding 

 vines native to the same region, is being experimentally grown 

 in parts of our own southwestern desert region, where there are 

 thousands of acres of unproductive, arid lands. Intisy, by virtue 

 of water storage tissues in the roots, can withstand long periods 

 of drought, so may be well adapted to growth in such regions as 

 those above. 



