AN (ECOLOGICAL SURVEY OF THE MIDLANDS OF NATAL. 527 



is nothing- but a monotonous succession of thorn ti'ees, etc., 

 here we have extremely xerophytic trees and shrubs growing 

 quite close to others which are not nearly so much so. Since 

 they are all to the same extent exposed to the dry hot winds, 

 the variability in their oecolog'ical character must be due to 

 the broken rugged nature of the slopes and the consequent 

 differences in soil conditions. 



The following species make up the rocky hillside formation 

 in the high veld region : 



Cussonia spicata, Brythrina tomentosa, Greyia 

 sutherlandi, Aloe natalensis, A. ferox, A. cooperi, 

 Buddleia salvisef olia, Chilianthus dy ssophyllus, 

 Heteromorpha arborescens, Combretum riparium, 

 Osteospermum moniliferum, Dombeya rotundif olia, 

 Ricinus communis, Ficus capensis, Zizyphus 

 mucronata, Panax gerrardi, Mtesa rufescens, 

 Vangueria infausta, Solanum auriculatum, S. 

 giganteum, S. sodomasum, Vernonia corymbosa, 

 Pavetta obovata, Burchellia capensis, Ehretia 

 hottentotica, Artemesia afra, Phytolacca stricta, 

 Buclea daphnoides, Plectronia spp., Royena pubes- 

 cens, Celastrus buxifolius, C. acuminatus, Lippia 

 asperifolia. 



If this list is compared with the others already given it will 

 be seen that there is an interesting admixture of close bush 

 and thorn veld species, as well as many others that do not 

 occur in these formations. The rocky hillside type is, there- 

 fore, not only intermediate in its oecological character, but 

 also to a certain extent in its composition between the 

 trees of the high veld and low veld regions. It is sometimes, 

 but not always, intermediate in position also, being found 

 immediately above the low veld. 



(2) The Low Veld Region. 



The rocky hillside formation in this region is the most 

 xerophytic of all plant formations in Natal. The rocky 

 slopes in this case usually overhang the rivers. Since these 



VOL. 2, PART 4. 35 § 



