CROP-PLANTS 349 



from this mixture, with the result that the crop provides the prin- 

 ciple source of revenue in Benue province. 



Palm-oil and palm-kernels, derived from the oil-palm {Elaeis 

 guineensis) , are the principal export of all the territories bordering 

 the Gulf of Guinea. The products also provide an important 

 ingredient of the local diet {see Chapter XVII) of the people of 

 West and Central Africa. Native rights of ownership are asserted 

 over all oil-palms and some authorities hold that the palm is never 

 really wild, but that its presence is an indication that the land has 

 been farmed at some previous time. The native farmer, however, 

 until recently, made no efforts to improve production other than 

 by periodical clearing of surrounding vegetation in order to plant 

 food crops. In the process fire frequently causes serious damage to 

 the palm-trees, and it is common in West Africa to see groves of 

 palms in which every tree shows a pronounced constriction near 

 the roots, where fires have eaten into the trunk. West Africa has 

 now to compete with the product of the large plantations of oil- 

 palms established in Sumatra and Malaya. This has stimulated 

 considerable research on breeding improved strains and on 

 methods of cultivation, while efforts are being made through the 

 agency of agriculture departments and co-operative organizations 

 to persuade Africans to grow palms in plantations instead of rely- 

 ing on chance seedling trees. 



The oil is obtained from two sources: palm-oil from the fleshy 

 pericarp of the fruit, and palm-kernel oil from the kernels. The 

 palm fruits of West Africa are of different types, varying from one 

 which has a very thick shell, a large kernel, but a thin pericarp, 

 to one with thin shell, small kernel, but a very thick pericarp. Most 

 of the palm-oil is obtained from the thin-shelled varieties, and the 

 kernel-oil from those with thick shells. The thin-shelled varieties 

 are, as a rule, not such heavy bearers as the others, s 3 the problem 

 of selecting improved palms is to combine the merits of both types 

 to produce a thin-shelled, high-yielding fruit. The breeding of oil- 

 palms, as of other perennials, is slow, since the young plants cannot 

 produce offspring for five or six years, and the final yield of the 

 adult tree cannot be estimated till it is fourteen years old, though 

 at about ten years, the proportion of oil obtainable from the 

 nuts can be determined. Thus the selection of oil-palms takes 



