THE PLANT ECOLOGY OF DRAKENSBERG RANGE. 541 



respect the habitat differs markedly from that of the thorn 

 veld. 



The tree-fern, Cyathea dreg'ei, is often fairly abundant 

 among* the Proteas, but it occurs at lower altitudes also. It 

 requires protection when young, so it favours sheltered spots. 

 It also demands plenty of water, so it is usually found near 

 the streams. The dwarf E n c e p h a 1 a r t o s ( E . g h e 1 1 i n c h i i ) , 

 a xerophytic form, is also associated. It favours rocky places, 

 and reaches an altitude of about 8000 ft. Protea veld is 

 most characteristic of the slopes below the Cave Sandstones, 

 where the soil is a loose, well-aerated one, derived from the 

 sandstones. The general distribution of the Proteas with 

 respect to the geological formations is indicated in the figs, 

 on pp. 515, 516, 517. 



This association of tree-growth with grass land is ecologically 

 of great interest. It shows that the factors which determine 

 the grassland type on the one hand, and those which deter- 

 mine the fox'est type on the other, are, in the case of Natal, 

 fairly delicately balanced. The thorn-trees of the thorn veld 

 which covers so much of Natal, occupying as it does all the 

 main river-valleys, represent a more progressive type than 

 the Proteas. The tendency in that case is for the trees to 

 close in and form thorn-thickets — a tendency which is 

 counteracted by the grass-fires. These exercise a similar 

 inlluence on the Proteas, though they are not, apart from 

 this, such a progressive type as the Acacias. They make 

 good firewood, and for this reason are rapidly disappearino- 

 from certain large districts. 



The Proteas in Natal are not altogether confined to the 

 Drakensberg. They occur on the Natal Table Mountain, on 

 Murchison Flats, and at Pinetown on the Table Mountain 

 Sandstone. The species Faurea salignais common at the 

 last-mentioned locality. Probably the explanation of their 

 somewhat peculiar distribution is to be found in the edaphic 

 factors. They prefer a loose, well-aerated soil, derived from 

 sandstone which is poor in lime ; and very probably the 

 differences apparent between thorn veld and Protea veld is 



