40 



Eubbek Producing Plants. 



Until the recent discovery of "Guayule" all known 

 rubber producing plants* were included in the four Natural 

 Orders of Euphorbiaceae, Moraceae, Apocynaceae, and As- 

 clepiadaceae. The addition of "Guayule" (Parthenium 

 argentatum) and Colorado rubber (Actinella Richardsonii) 

 introduces another order, viz. Compositae. An addition to 

 the Asclepiadaceae is furnished by a new introduction from 

 Angola and Zambesi called Encanda rubber, and described 

 as Raphionacme utiUs. There are five other Natural 

 Orders of which some genera are said to be lactiferous 

 plants but of theoretical interest only.f 



The arrangement of the different families of com- 

 mercial rubber plants is as follows : — t 



Euphorbiaceae: — Hevea, Manihot, Micrandra, Sapium. 



Moraceae: — Ficus, Castilloa. 



Apocynaceae: — Landolphia, Funtumia, Car pod inns, Cli- 

 tandra, T abernamontana , Mascarenhasia, Hancorn ia T 

 Forsteronia, Willughbeia, Urceola, Leuconotis, Melo- 

 dinus, Parameria, Chonemorpha, Chilocarpus, Dyera, 

 Alstonia. 



Asclepiadaceae: — Cryptostegia, Raphionacme. 

 C oat po sitae : — Pa > ■ t It ei i k im, Act in ell a. 



Rubber Sources. 



The world's output of raw rubber is stated to be as 

 follows : — 



South America (including Mexico) 43,000 tons. 



Africa 22,000 tons. 



Eastern and Indo Malaya . . . . 500 tons. 



Total 65,000 tons. 



All of this output is forest or wild rubber.^ From 

 South America the bulk of rubber is obtained from Para 

 rubber (Hevea Braziliensis). Other supplies are Ceara 

 rubber (Manihot Glaziovii and Manihot sp:) Caucho ball, 



*The guttas (or getah percha) belong to the N. O. of Sapotaceae and include 

 Dichopsis, Plaquium, Payena, and Mimusops. 



t Kew Bulletin No, 4,1908, P. 199. 



% The Malayan species of Artocarpus (getah tamp and tampang) are not 

 clashed as commercial rubbers. 



§ About 1000 tons of plantation rubber is not included in this estimate. 



