6 



-are nowhere dominant, (2) open grassland formation of the 

 Western side, much of it semi-desert, (3) the Karroo, (4) the 

 Sand Veld of the Kalahari, (5) the Grassveld of Eastern Cape 

 'Colony, Natal, the Eastern part of the Free State, and the 

 Transvaal, a widely extended type of formation of which 

 there are several sub-types or varieties which may or may not 

 be considered sufficiently distinct to rank as separate forma- 

 tions. (This type will often he referred to in the following pages 

 as "the grass veld of the Eastern side" or "Eastern grass 

 veld"). (6) Succulent and Thorny Scrub of the dry river 

 valleys — the climax of Thorn Veld, (7) Forest. 



The Associalion is a climax community with two or more 

 ■dominants, e.g., a Yellow-wood-Black Ironwood forest. The 

 Associations are units which are associated regionally to con- 

 stitute the formation. 



The Consociation is the unit of the association charac- 

 terised by a single dominant, e.g., Falcate Yellow-wood forest 

 or Anthistiria (red grass or insinde) veld. 



The Society is a climax community characterised by 

 a sub-dominant, or sometimes by two or more sub-dominant 

 species. Societies of various species of the large grass genus 

 Andropogon are very common in much of our eastern grass 

 veld. The society is a localised or recurrent dominance 

 within a dominance. Clements distinguishes (1) Aspect 

 Societies which dominate only for a season, e.g., in spring, 

 and are replaced later by other societies. We thus find Pre- 

 vernal, Vernal, Aestival, and Autumnal aspect societies. Of 

 these the vernal and aestival are of most importance in South 

 African grass veld. (2) Layer Societies very conspicuous in 

 woodland but occurring in grassland also. The different 

 types of vegetation are arranged in layers, and the develop- 

 ment is usually seasonal as in the aspect societies. (3) Crypto- 

 gam ic Societies consisting of lower forms of plant life such as 

 the Mosses. 



The Clan ranks below the society in importance, but 

 there is no hard and fast line to be drawn between them. The 

 clan is local or restricted to a few scattered areas. 



It is necessary to lay emphasis on the fact that all the 

 above are climax communities, belonging to the final stage 

 •of the plant succession. 



Throughout the succession there are similar or analagous 

 communities, which do not belong to the climax stage, but 



