660 LXXXII, APOCYNACER. [ Pacouria 
LXXXII. APOCYNACE. 
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 primeval 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 Pacowria. All the species 
of Pacouria 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. owariensis 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 sufficiently remunerative price in the 
markets on the coast to encourage the natives and dealers to 
devote themselves to the collection and marketing of this valuable 
commodity. 
1, PACOURIA Aubl. Hist. Pl. Guian. i. p. 268, t. 105 (1775). 
Alstonia Scop. Introd. p. 198 (1777), non Br. (1809). Vahea 
Lam. Encycl. Méth. tab. 169 (1797 %). Landolphia P. Beauv. FI. 
Owar.i. p. 54, t. 34 (1806 2); Benth. & Hook. f. Gen, Pl. itp, 692, 
The type of Aublet’s genus isin the British Museum herbarium. 
