December 1, 1911.] 



THE INDIA RUBBER WORLD 



113 



African Grass Rubber. 



By F. H. Hunicke. 



UNDER the general term of African Grass Rubber Plants 

 the following are included: 



(I) Landolt>hia Tholonii; (2) Laitdolphui HidiiiUs; (3) 

 Carpodiiius Lcucantha : (4) Carpodiims Cliyllorhha; (5) Carpo- 

 dinus Gracilis. 



The first two are found in the Congo Basin, i. e., in the 

 French and Belgian Congos, in Nigeria and in the northern 

 part of Portuguese Angola. The other three may be classed as 

 the grass rubber plants of Angola, where they are still found in 

 relative abundance. These also extend somewhat into German 

 Southwest Africa. The general distribution of these five varie- 

 ties is indicated on the chart on following page. 



In addition to the above, various writers include the Carpo- 

 dinus Lanccolata and the Clifandra Henriquesiana, designating 

 them as false rubber plants, or, in other words, as plants pro- 

 ducing latex which does not contain rubber. Anyone at all con- 

 versant with tropical plant life will concede that there are in- 

 numerable trees, vines and shrubs which give forth a white milky 

 sap similar to the usual rubber latex, yet these are never referred 

 to as false rubber plants. 



The term "grass rubber plants" is distinctly a misnomer, for 

 none of the above varieties could, under the most liberal con- 

 struction of the word, be included under the general classification 

 of grasses. They are distinctly species of shrubs, as may be 

 readily seen by reference to the photographs of the three varie- 

 ties found in the Congo Basin. They should be called "root 

 rubbers," as the rubber is invariably extracted from the roots. 



The peculiarity or principal characteristic of these plants is 

 that the shrub is of comparatively insignificant size, while the 

 roots, which contain the latex, are of unusual length. It is a 

 very common occurrence to find the shrub of the Landolphia 

 Tholonii, which is by far the most important rubber producer. 



laced and entangled 

 generallv found it i 



In the sandy soil in which the plant is 

 a simple matter to pull up the laterals 

 without any tools except a 

 machete to cut such other 

 roots as may have grown 

 across and over the laterals. 

 The specimen of Landol- 

 piiia Tholonii, shown in the 

 photograph, measures but 

 eleven inches in height. It 

 represents a fair average 

 sample. The Carpodinus 

 i iiiiccolata. or false rubber 

 plant, will commonly reach 

 eighteen to twenty-four 

 inches, while the Landolphia 

 Huniilis is often found as 

 high as twenty-four to 

 thirty-six inches. On the other hand, the root systems of the 

 three plants, as regards size, range in inverse order, that is to 

 say, while the Landolphia Huniilis is a very much larger shrub 

 than the Landolphia Tholonii, its underground development is 

 very much smaller. 



The roots of the two Landolphias are very similar, and they are 

 not easily distinguished from each other except when they are 

 thoroughly dry, when, by breaking them, the greater rubber con- 

 tent of the Landolpliia Tholonii is at once evident. The unusual 

 feature of the latter root is that the bark consists of innumerable 

 separate pores which extend longitudinally throughout the length 

 of the root. All of these pores contain thick rubber latex. When 

 ti-e root is pulled out of the ground the latex is in the usual liquid 

 form, but this coagulates very quickly when exposed to the 



Cross-section oi- the root 

 I,.\NDOLPHiA Tholonii. 



Carpodinus Lakceolata. 



Landolphia Tholonii. 



Landolphia Humilis. 



but ten to twelve inches in height above the ground, while 

 underground, radiating from a small tap root, there may be 

 several lateral roots which reach a length, at times, of twenty 

 and even thirty feet. These laterals are about one-half inch 

 thick near the tap root and gradually taper down towards the 

 ends. They are seldom nice than three inches under the sur- 

 face of the ground. The lateral roots send up new shoots which, 

 in turn, form new plants, so that the root system in a fairly 

 dense field of Landolphia Tholonii becomes considerably inter- 



atmosphere. This change takes place so rapidly that it was found 

 impossible to squeeze the latex out of the roots by running it 

 through a small sized crusher, similar to the ordinary clothes 

 wringer, immediately after the root was pulled out of the ground. 



On breaking a piece of dry root it will be found that in each in- 

 dividual pore the latex has coa.gulated into a fine thread of white 

 rubber. Pulling the two pieces of the broken root apart reveals 

 a complete circle of white silk-like rubber threads. 



The crude method of extracting the rubber as practised by the 



