272 J. \y. BEws. 



(3) TEMPERATURE. 



As regards temperature the following- are tlie most impor- 

 tant points : 



1. Altititde. — ^On the coast the temperature hardly ever 

 falls below freezing-point. This absence of frost from the 

 coast-belt is undoubtedly the most important fact as far as 

 temperature is concerned, since certain species are able to 

 grow which could not exist further inland, for the reason 

 that they would be killed by the winter frosts. In general 

 there is a fall in the mean temperature corresponding to 

 altitude. This fall may be taken as 8° F. per 1000 ft. Con- 

 sequently it is not difficult to find species characteristic of the 

 different zones from the coast upwards, and Thode ^ has 

 attempted to divide Xatal into botanical regions according 

 to altitude. As will be pointed out later there is a change in 

 the bush from the coast upwards, but the difference is more 

 floristic than oecological. Afi a matter of fact many of the 

 dominant species, especially in the (Irass Savannah, extend 

 from the coast right up to the Drakensberg. 



2. VAiaATioN IN Temperature. — There is much less variation 

 in temperature on the coast-belt, due largely to the amount 

 of cloud. The daily range is not nearly so great. It is 

 neither so warm at mid-day nor so cold at night. In the 

 midlands in the winter months a difference of 50° F. in daily 

 shade temperature is not at all uncommon, and at sunset the 

 fall is often extremely sudden. These sudden changes in 

 temperature form one of the most striking features of the 

 Natal climate. 



3. Temperaturk of Valleys. — In the winter season the 

 valleys contain air which is much colder during night 

 time than that of the higher levels of the hills and ridges. 

 As one descends into a valley a sudden change in tempera- 

 ture is noticeable. It may be quite warm down to a certain 



1 Thode, Justus, ' The Botaiiiciil Regions of Niital determined )jj 

 Altitude." Duvhaii, ll»ol. 



