THE PLANT ECOLOGY OF THE COAST BELT OF NATAL. 415 



characteristic isolated clumps are formed which grow larger. 

 More pioneers fill in the intervening spaces and finally scrub 

 is formed. In the moister climatic areas such scrub may 

 give way later to forest, but in the drier parts the Acacias 

 and Euphorbias remain dominant and the thorn scrub thus 

 formed is a climax type. 



The tree veld type of plant succession also occurs in the 

 hydrosere, the pioneers being hygrophilous species of trees 

 which will again be referred to in connection Avith coast- 

 scrub and forest. The umDoni or Waterboom (Eugenia 

 cord at a) is the most important (PI. XXIV, fig. 2). It is 

 very common on the south coast behind the dunes, colonising 

 all the moister types of grassveld. It is often followed by 

 Strelitzia augusta. The figs (Ficus capensis and F, 

 natalensis) also belong to the hydrosere and act as pioneers. 

 Other species will be referred to later. 



Tree veld generally is most abundant in the neighbourhood 

 of scrub of one kind or another, either xerophytic, thorny 

 and succulent scrub in tlie drier parts or mesophytic scrub in 

 moister parts, or hygrophilous scrub in very moist situations. 

 The scrub species are naturally transported into the tree veld, 

 but the essential point on which emphasis is laid is tliat the 

 tree species are the pioneers and only a few are able to act as 

 such, and a park-like type is the precursor of the denser scrub. 



Since the total list of species which occur in coast tree 

 veld is somewhat extensive, it has been thought well to 

 arrange them according to the families to which they belong, 

 indicating at the same time the nature of their growth forms 

 and giving their relative frequency. The symbols used have 

 the usual significance (d. = dominant, l.d. ^ locally dominant, 

 a. = abundant, l.a. = locally abundant, f . =^ frequent, 1. = local, 

 o. =: occasional, r. = rare). 



Capparide.e. — Cadaba natalensis (261), scrambler (o.) ; 

 Niebuhria triphylla, shrub or tree (o.) ; Capparis citri- 

 folia (l.a.), C. corymbifera (379) (l.f.), C. gueinzii (l.a.), 

 C. zeyheri (214) (l.a.), all climbers. These climbing species 

 naturally appear after the pioneers have become established. 



VOL. 4, PAET 2. 28 



