olO J. W. BEWS. 



Upper Districts. 



Acacia horrida, 



Acacia caff r a var. rupestris, 



Acacia sp. (liirtella ?), 



Celastrus buxifolius, 



K h r e t i a li o 1 1 e n t o t i c a^ 



Zizyphus inucronata. 



More Coast wards. 



The above, together with — 



Acacia arabica var. kraussiana, 



Dichrostachys nutans, 



Commiphora spp. (carytefolia), 



Sclerocarya caffra, 



Clerodendron g- lab rum, 



Erythrina caffra, 



Harpephyllum caffruui. 

 The form assumed by these trees varies somewhat. The 

 urabrella-form with flat-spreading crown is most typical. 

 Acacia caffra, Celastrus buxifolius, Zizyphus 

 mucronata, Acacia arabica var. kraussiana, Dichro- 

 stachys nutans always have it in the Thorn Veld, but 

 Zizyi^hus and Celastrus also occur in the close bush (see 

 lists), and there they do not assume the virnbrella-form. Of the 

 others. Acacia horrid a, and Acacia s p. (h i r t e 1 1 a ?) usually 

 have the same form. Sclerocarya caffra and Clero- 

 dendron glabrum often have it. The others are usually 

 rounded or vary in form. The flat-crowned form is well 

 adapted to Avithstand the strong hot winds to which the 

 trees are fully exposed. Another possible factor operating 

 in this respect is the circumstance that their water supply is 

 so limited that their growth in height is also restricted. They 

 all have large root-systems though usually they do not pene- 

 trate to any great depth, but rather extend along the surface 

 of the soil. 



When we come to consider the cause of the trees o-rowinsr 



