660 LXXXII. APOCYNACE.E. [Pc 



LXXXII. APOCYNACEiE. 



Rubber-yielding plants appear to be abundant in Angola, 

 although the quantity of rubber exported in Welwitsch's time 

 was very scanty, and in some cases had been even restricted to 

 single samples ; he, however, was fully convinced that the small- 

 ness of the export of an article in such great demand in European 

 markets was by no means to be attributed to the rarity of these 

 plants in the country, but principally to the immense variety and 

 quantity of several other colonial products, such as ivory, wax, 

 gum copal, palm oil, coffee, etc., on which both the native collectors 

 and the local dealers derive a much larger profit. Moreover, the 

 negroes of tropical Africa are very imperfectly acquainted with or 

 totally ignore the superior methods and manipulations employed 

 in America and the East Indies. According to Welwitsch's 

 observations and investigations made in Angola, the trees and 

 shrubs from which indiarubber is collected, besides some large- 

 leaved species of Ficus, are several species of Pacouria, the latter 

 forming large climbing shrubs, 50 to 80 feet high, with stems not 

 rarely attaining 6 to 8 in. in diameter, when growing undisturbed 

 in the primaeval forest and spreading out their branches like a 

 verdant carpet over the tops of the larger trees. A species also 

 of Pleiocarpa, growing in the less dense forests of the interior, 

 yields a rather valuable kind of rubber, though only in small 

 quantity on account of the tree rarely attaining much size and 

 its sap not being so milky as that in Pacouria. All the species 

 of Pacouo'ia observed by Welwitsch produce edible fruits, those of 

 P.florida being the most appreciated by the natives and called by 

 them " Diluti," a name which they also apply to the shrub itself, 

 while P. oivariensis as well as the rubber extracted from it they 

 call " Licongue." The method which Welwitsch saw employed 

 in some of the highland districts by the Licongue collectors was 

 very rude and imperfect ; by the imperfection of the method of 

 extraction, not only the quantity of the product must have been 

 considerably reduced but also the quality of the article obtained 

 was much inferior to what could be collected by a more appropriate 

 and scientific process ; it is, therefore, not surprising that the 

 rubber did not fetch a sufiSciently remunerative price in the 

 markets on the coast to encovirage the natives and dealers to 

 devote themselves to the collection and marketing of this valuable 

 commodity. 



1. PACOURIA Aubl. Hist. PI. Guian. i. p. 268, t. 105 (1775). 



Ahtonia Scop. Introd. p. 198 (1777), non Br. (1809). Vahea 

 Lam. Encycl. Meth. tab. 169 (1797 ?). Landolphia P. Beauv. Fl. 

 Owar.i. p. 54, t. 34 (1806 ?) ; Benth. & Hook. f. Gen. PI. ii.p. 692. 



The type of Aublet's genus is in the British Museum herbarium. 



