360 THE BOOK OF USEFUL PLANTS 



Ceylon and the Malay Peninsula, where English 

 companies have started great plantations. Be- 

 tween 1900 and 1910, Para rubber rose in price 

 from three shillings to twelve shillings per pound ! 

 It costs about one shilling per pound to collect 

 from the wild or to produce in plantations. 

 The price fluctuates in the hands of speculators, 

 quite independent of supply and demand. 



Central American, or Panama rubber is from a 

 tree called Castilloa elastica, which grows ten 

 degrees north of the equator. The rubber has not 

 the strength of Para, and brings a lower price. It 

 is the tree of Mexican and Honduras plantations. 



A tree that reaches sixty feet in height, and 

 yields rubber almost equal to Para, is Sapium 

 Jeumani, that grows in Colombia and Guiana. 

 In cultivation, it does surprisingly better than in 

 the wild. 



The "India rubber" plant of the northern 

 greenhouses, Ficus elasticus, is the Assam rubber 

 tree in its East Indian forest home. It may begin 

 life as an air plant, fixing its roots in the crotch of 

 another tree in which a seed has lodged. A shock 

 of aerial roots strike downward, and reach the 

 ground, after which the top depends upon food 

 drawn from the earth, and the supporting host 

 tree is no longer needed, for the rubber tree by 



