PLANT SUCCESSION. 243 



Cussonia spicata is the chief pioneer in the invasion of the 

 grassland, though its place is occasionally taken by Comb re tain 

 kr&rissii or Glerodendron glabrum. A detailed analysis of several 

 ■clumps is given to show the principal variations in their com- 

 position. 



Comment is made on the large number of dead Cussonias on 

 the hillside, and evidence is adduced to show that death is due to 

 the attack of white ants. 



In conclusion I must acknowledge the encouragement and 

 assistance which I have received from Professor Bews, who has 

 taken a keen interest in the present investigation. I must also 

 express my thanks to Dr. T. R. Sim for assistance in the deter- 

 mination of many species, and to Mr. R. U. Sayce for help in 

 the preparation of the accompanying map. 



References. 



<1) Bews, J. W. : "The Vegetation of Natal." Ann. Natal 31 us., 



vol. ii (1912), p. 253. 

 •(2) — "An Ecological Survey of the Midlands of 



Natal." etc. Ann. Natal Mus., vol. ii 



(1913), p. 485. 



(3) "An Account of the Chief Types of Vegeta- 



tion in South Africa, with Notes on the 

 Plant Succession." Journ. Ecoloc/t/, 

 vol. iv (1916), p. 129. 



(4) "The Plant Succession in the Thorn Veld." 



S. A. Journ. of Science, xiv (1917), p 153. 



(5) "The Plant Ecology of the Drakensberg 



Range." Ann. Natal Mus., vol. iii 

 (1917), p. 511. 



(6) "The Plant Ecology of the Coast Belt of 



Natal." A nn. Natal Mux., vol. iv (1920), 

 p. 367. 



(7) Aitken, R. D., and Gale, G. W. : "Botanical Survey of Natal 



and Zululand. A Reconnaissance Trip 

 tli rough North-eastern Zululand." Botani- 

 cal Surra/ of South Africa, Memoir 2 (in 

 the press). 



Explanation of Plates II and III. 



Plate II, Fig. 1: Signal Hill. The "central valley" is on the 



right and scattered clumps are to the east 

 of this. 

 Fig. 2: Clump 2. For description see text. 

 Pl\te III, Fig. 3: A fully formed clump. Note the open space 

 in the centre. 

 Fig. 4: For description see text. Note the dead 

 Cussonia in the foreground. 



