372 SCIENCE IN AFRICA 



One-third of the crop is produced on large estates and the rest by 

 some 600 independent planters, of whom many are Indians. Re- 

 search work is done at the Sugar Association Experiment Station, 

 Mount Edgecombe, near Durban, of which Mr. Dodds is Director. 

 Since 1926 the commercial cultivation of varieties other than Uba 

 has been prohibited owing to their susceptibility to mosaic disease. 

 Recently, however, improved varieties have been selected which 

 may replace the Uba cane; the best are POJ 2725 and POJ 2878 

 from Java and CO 290 from India. Experiments on varieties 

 resistant to streak disease are in progress at the Natal Herbarium. 



Selection work is also being done in Kenya, Uganda, and the 

 Gold Coast. An account of that in Uganda is given by the mycolo- 

 gist, Mr. C. G. Hansford (1935a), who has also made a study of 

 the diseases of sugar-cane (1935b). In the Gold Coast the agri- 

 cultural department is making a collection of imported types at 

 Kumasi. Sugar-cane is cultivated in Mozambique in the valleys 

 of the Zambesi, Limpopo, and Incomati rivers. The area under 

 cultivation during 1929-30 was 22,500 hectares, and 70,000 tons 

 of sugar were exported. 



Kola nuts, which are chewed as a stimulant, are produced in 

 West Africa from the trees Cola acuminata and Cola nitida. In Sierra 

 Leone the kola trade is old-established; the territory has exported 

 nuts to neighbouring African territories for a number of years, 

 though latterly the imposition of protection and the development 

 of local production have closed many of their former markets. 

 Some trees, which produce inferior nuts, grow wild, but nearly all 

 the product is obtained from trees grown by individual natives in 

 their cultivation plots. Since the crop involves very little labour, 

 production is steadily increasing. In Nigeria kola trees have been 

 planted with success by the agricultural department on the poor 

 soils at Benin and in the Eastern districts, where cacao cannot be 

 grown, and the crop has assumed considerable importance. 



The cultivation of wattles [Acacia mollissima and A. decurrens) is 

 spreading in British Africa. The position with regard to wattle 

 bark and other tanning materials has been summarized in a bulle- 

 tin of the Imperial Institute (1927). The trees were first introduced 

 to South Africa from Australia for use as pit-props, but an export 

 of bark for tanning was soon established. Natal is the centre of 



