Effects of a Bush Fire on the Vegetation of Signal Hill. 
231 
The Peninsula flora is characterised by the presence of certain families 
which are typical of the south-western districts, but are either lacking or 
scarce in South Africa beyond these limits. The area under discussion is 
singularly deficient in a number of these families. Bruniaceae and Pene- 
aceae are entirely absent, the family Restiaceae is represented by a single 
specimen, and members of Proteaceae, Rutaceae, and Ericaceae are only 
occasionally seen. 
It has been suggested, especially in the case of the Proteaceae, that bush 
fires have been largely instrumental in eradicating large numbers of species 
from these slopes. This suggestion, however, does not explain why it is 
that most of the families mentioned above are well represented on the 
slopes below Lion's Head, which slopes in their vegetation incline to the 
true " Macchia " type. It is significant that the soil here is derived from 
granite (fig. 1), and as bush fires have occurred in plenty, it seems reasonable 
to conclude that the soil may be the determining factor in the case. 
The problem needs further investigation, but certain facts such as the 
dominance of Blaeria ericoides at certain spots on the granite soil, and the 
scarcity of the family Ericaceae on similar positions on the slate, lead one to 
the conclusion that the soil in this particular instance has a profound 
influence on the vegetation. 
My thanks are due to Professor Thoday for his kindness in taking the 
photographs which illustrate this paper, and for the many helpful criticisms 
which he has offered from time to time during the progress of the work. 
Summary. 
1. The bush fire, the effects of which are recorded, broke out on the 
5th February 1919 and burned for two days, killing all the aerial parts of 
plants on the slope. 
2. About three weeks later considerable growth had taken place in 
Asparagus capensis and Andropogon hirtus. Shortly afterwards Haemanthus 
■coccineus and a few other less notable plants were in flower. Various species 
of Rhus were putting up shoots. 
3. The early winter and spring flowering periods were characterised by 
-an abundance of vigorous flowering shoots. These appeared at the usual 
time. In the majority of cases these plants possess underground storage 
organs. Progressive decrease in numbers and vigour of plants flowering 
during these periods was noted in 1920 and 1921. Suggestions are made to 
account for the phenomenon. 
4. Numerous seedlings came up during the winter of 1919, but in general 
these were not identified till the next year. 
