An Account of the Chief Types of Vegetation in South Africa, with Notes on the Plant Succession

Abstract

It seems to be an unfortunate necessity for any writer, who uses the term in connection with the study of vegetation to endeavour to define what he means by it. Plant Ecologists, however, are fairly well agreed that the term formation should be applied to certain natural units of the vegetation. The difference lies in the methods of determining the units. Most of the European continental ecologists including Schimper (22), Warming (30) and Drude (12), use to express definite physiognomic types. The British ecologists (28), on the other hand. emphasize the habitat as determining the formation. Since the climate of the British Isles is relatively uniform, habitat comes to be mainly a question of soil conditions and soil therefore is the master factor adhered to by the British ecologists in their system of classification. This is perfectly justifiable and in fact necessary where the climatic factors are more or less uniform. In South Africa, however, climate is on the whole more variable than soil conditions though they both vary. To use soil as a basis of classification for South African vegetation would hardlv succeed. Even in small areas climate is more important, as for instance in the Cape Peninsula, that wonderful botanical area which though only 197 square miles in extent, or a little larger than the Isle of Wig,ht, yet, according to Bolus and Wolley-Dod's list (6) has no fewer than 2117 species of flowering plants. The one side of Table Mountain has Bush of the Eastern type, the other side sclerophyllous heath and Macchia. This striking difference is here certainly not due to soil conditions but to the marked difference in clinmate due to the S.E. mist and rain clouds. Bolus states that the annual rainfall for an average period of ten years varies between 21 and 28 inches for various stations on the N.W. side, while on the S.E. side it varies between 43 and 63 inches.