52 



Alstonia scholar is (getah Pulai) has a wide distri- 

 bution, from India, throughout the tropics of the East. 

 The rubber is not so easily prepared as that of jelutong but 

 considering the abundance of this tree — particularly in Su- 

 matra — it will most probably be soon in demand. It is 

 fairly common in the Malay Peninsula — a much smaller 

 tree than Dyera costulata but grows from self sown seeds 

 almost everywhere. 



ASCLEPIADACEAE. 



Cryptostegia prandiflora is a well known plant from 

 Madagascar and is grown in nearly all Botanic gardens for 

 its handsome flowers. The rubber is reported as being of 

 fair grade but the cost of collecting it is prohibitive, as the 

 plant is of small dimensions — a bush or low limber. 



Raphidhacme utilis (Encanda rubber) is a recent dis- 

 covery from Angola. It differs from all other known rub- 

 ber plants, "it is a herbaceous stemless plant with a tuber- 

 ous shaped root" a tuber like a small garden turnip with a 

 few stemless leaves. As far as is known at the present 

 time the rubber is difficult to separate and prepare. Some 

 laboratory samples show a very high return of caoutchouc 

 but the time and expense eliminating resins and other 

 matter is considerable. Nearly all the African tubers im- 

 ply a group of plants peculiar to arid regions. The tuber 

 contains a viscid fluid or storage of sap enabling the plant 

 to survive long periods (2 or 3 years) of drought, and I 

 surmise that it is the difficulty of separating the latex from 

 the contaminating sap of the tuber which detracts from its 

 successful preparation. It is a fascinating plant and fur- 

 nishes a high grade rubber, but considering the probable 

 expense of preparation, the uncertainty of a mature crop, 

 and its desert origin, there is little likelihood of it ever 

 reaching the market as plantation rubber. 



Com i*o$i tar. 



Parthenium argentahim (Gayule rubber) is a recent 

 introduction from Mexico and Central America. A low 

 herbaceous bush of slow growth but found wild over large 

 areas of Central America. Although a low grade rubber 

 it has excited considerable interest in the rubber trade as 

 a cheap adulterant and substitute of better rubbers — thanks 

 to the advance made in the better treatment of all rubbers 

 by chemists and manufacturers — and brought into use 

 many lines of cheap rubber goods which would not have been 

 otherwise saleable, owing to the high cost of raw rubber. 

 The rubber is obtained from all parts of the plant, the bush 



