T[1E PLANT ECOLOGY OF THE COAST 1!LLT OF NATAL. 389 



where more sliade-lovino-, inesopliytic species, that in moister 

 places follow thein and kill them out, are not able to do so. 

 I'he recognition of this fact appears to be of the utmost 

 importance in any analysis of the distribution ot" plants over 

 South Africa generally, but since it does not apply only to 

 the Natal coast belt, a full discussion of details is reserved 

 for a future paper. It may, however, be pointed out here 

 that in a continental area like South Africa, with its great 

 variations in climate, the underlying principles of plant 

 succession probably have far more to do with determining 

 the area occupied by species than the mere age of the 

 species, as postulated by Willis.^ 



Y. THE PLANT COMMUNITIES. 



The different types of plant comnmnity will be dealt with 

 in the order of the plant succession, the initial or relatively 

 primitive types being considered first, then the semi-stable 

 intermediate or ti^ansitional types, and finally the climax 

 yssociatious. As has been pointed out elsewhere," it is 

 doubtful whether any of the coast grassveld can be con- 

 sidered a climax tyjie. It seems to be everywhere unstable, 

 and merely a stage in the succession to scrub or forest. At 

 most it may be considered as semi-stable or sub-climax. The 

 only true climax types are the psammophilous bush, which 

 clothes the line of fixed sand-dunes close to the seashore, the 

 coast forest, which occurs behind the dunes on the resc of 

 the coast belt, and a xerophytic thorny scrub, which is found 

 in the drier, hotter hjcalities. It must remain a matter of 

 opinion whether even the first two types should be kept 

 distinct, or whether the associations composing them should 

 be grouped together in the same formation. A very large 

 number of species, including those that are sometimes 



' Willis, J. C, •• The Endemic Flora of Ceylon, with Reference to 

 Geographical Distribution and Evolution in General," ' Phil. Trans.,' B, 

 vol. ccvi, 1915. " The Evolution of Species in Ceylon, with Reference 

 to the Dying Out of Species," ' Ann. of Botany,' vol. xxx, 1916. 



" Bews, J. W., ' The Grasses and Grasslands of South Africa,' 

 Pietermaritzbnrg, 1918. 



