164 SCIENCE IN AFRICA 



and found it to be closely similar to that of the East African moun- 

 tains, and J. Mildbraed (1930) has given an accurate enumeration 

 of rain forests, one of the few works of its kind yet published for 

 Africa. M. Aubreville (1932), chief of the forestry service in 

 French West Africa, has produced a full account of the different 

 types of forest, rain — deciduous — mangrove, etc., and their distri- 

 bution in the Ivory Coast. 



For the Abyssinian flora C. L. Collenette (1931) has given a 

 general physiographic account, and J. Gillett, who accompanied 

 the Somaliland-Ethiopian Boundary Commission of 1933-4 ^^ 

 botanist, will be publishing shortly on both British Somaliland 

 and Abyssinia. 



Swamp vegetation and water-supply 



It is difficult to select any particular aspect of plant ecology for 

 special attack, but it may be stressed that the most immediately 

 useful results can be achieved by the exhaustive survey of restricted 

 types of plant habitat. Attention may be directed, for instance, 

 to the vegetation of swamps which has a most important role in 

 the natural economy in many parts of Africa. 



From one point of view swamps seem responsible for great loss 

 to Africa in that they soak up and evaporate water which might 

 otherwise be utilized. It is estimated that the sudd areas of the 

 White Nile together with the papyrus swamps around Lakes Kioga 

 and Victoria are responsible for the loss by transpiration of some 

 50 per cent of that river's water. Hence large-scale engineering 

 work is proposed to short-cut the sudd area and thus increase the 

 supply of water from Central Africa to the Sudan and Egypt (see 

 Chapter II). 



On the other hand, some authorities consider the swamps to be 

 the most important natural water-reservoirs of Africa. If the swamp 

 plants are destroyed, the swamps and vleis will disappear and the 

 streams which rise from them will become intermittent or cease to 

 exist. From this point of view the preservation of swamp vegetation 

 is as important as that of forests. 



Clearly there is here a problem calling for intensive research on 

 the exact part played by swamps in hydrology, and the probable 

 results of draining swamps or cutting the vegetation. It has some- 



