CHAPTER XII 



THE AFRICAN RUBBER VINES 



African Rubber Vines. — The rubber vines belong to the 

 two natural orders Apocynaccae and Asclepiadaceae, 

 those of the former order being much the more important. 

 They occiu: especially in tropical Africa, where they are 

 very widely distributed, and are also found in Asia and 

 America. Lists of the principal rubber vines, with their 

 geographical distributions, have been given previously 

 (see pp. 40-1), and in the following account it is proposed 

 to deal in detail with the African vines. 



The prmcipal rubber-yieldmg vines occurring in 

 Central Africa belong to the three genera Landolphia, 

 Clitandra, and Carpodinus of the natural order Apocy- 

 naceae, whilst species of Cryptostegia belonging to the 

 order Asclepiadaceae are found in ]Madagascar. A 

 number of other genera of the Asclepiadaceae, e.g. Peri- 

 ploca, Dregea, and Asclepias, are represented by rubber- 

 yielding species, but these plants are of little value 

 as commercial sources of rubber. The most important 

 African vines are Laiidolphia Heudelotii, A. DC. ; Landol- 

 phia owariensis, Beauv. ; Landolphia Klainei, Pierre ; 

 Landolphia Kirkii, Dyer ; Landolphia Dated, Stapf ; and 

 Clitandra orientalis, K. Schum., with the closely related, 

 if not identical, forms Clitandra elastica, Chev., and 

 Clitandra Arnoldiana, De Wild. The vines of lesser 

 importance are included in the previous list already 

 referred to. 



In addition to the vines there are a number of bushy 

 plants belonging to the genera Landolphia, Clitandra, and 

 Carpodinus which furnish " root rubber " from their under- 

 ground stems (rhizomes). The chief of these are Landolphia 

 Thollonii, Dewevre ; Landolphia parvijolia, K. Schum. ; 



