216 A NATURALIST IN MID-AFRICA. 



In the " Journal of the Linnean Society," vol. 

 xxx. p. 67, I have attempted to determine by the 

 statistical method the most natural African floral 

 regions. 



Taking the figures there given, I find that 498 

 species of the order Rubiacese found in Tropical 

 Africa occur as follows : — 



The Westerly Wet District contains 280 species, 

 or 56 per cent. 



The Easterly Wet Division contains 58 species, 

 or 11.6 per cent. 



Abyssinia and Angola, which may be regarded as 

 parts of the Central Ridge, contain 39 species, or 

 5.8 per cent. 



The exceptions, that is plants common to East 

 and West Tropical Africa, are 18 in number, or 3.6 

 per cent., and amongst this small proportion are 

 such weeds of cultivation as Oldenlandia, &c. 



The most interesting region of African botany is 

 the third, the Central Watershed, or ridge of high- 

 lands that extends from Abyssinia by Ruwenzori 

 down to the Livingstone mountains and Steven- 

 son Road, and may even be traced, I think, to the 

 Cape Colony. 



It consists usually of a series of grassy ridges, 

 though in some places it is covered by scattered 

 trees, not dense enough to constitute forest and 

 not isolated enough to form the park-like country 

 which one occasionally sees in the lower levels. 

 The river valleys are often, or usually, covered 



