Origin of the Angiospermous Flora of South Africa. 



325 



fully invaded this region, and has spread to such an extent as to 

 become its greatest pest, is a species of Opuntia (perhaps 0. tuna) 

 from the drier parts of Mexico and Central America. The connec- 

 tion with the South-Western Eegion is but a slight one, for while 

 many typical Karroo plants have apparently invaded the latter, there 

 are but few of the peculiar South-Western types to be found here. 

 The few ButacecB, Ericacece, and Bestionacece which appear are mere 

 stragglers on the nearer mountains ; while Bruniacece, Proteacece,. 

 and Penceacecd are, as far as we know, entirely absent." Other 

 writers have also commented on the antiquity of the Cape Flora. 

 Of these I will only quote Diels (1905, p. 73), as his remarks have 

 also some bearing on another aspect of our problem which will be 

 discussed later on. He says : "■ The Flora of South Africa in its 

 resistance to intruders from other countries is in striking contrast 

 to the Flora of New Zealand which is flooded by European colonists 

 and weeds. Perhaps this can be explained by the supposition, 

 which is also supported by other facts, that the conditions under 

 which the South African plants have flourished, have persisted in 

 their main features for countless ages, while in New Zealand 

 the xerophytic Flora can only be looked upon as a remnant of 

 bygone ages, when the present New Zealand was only a portion 

 of a large expanse of country in which large plains extended in an 

 eastward direction. These plains must have been much drier than 

 the present New Zealand, and were the home of the Xerophytes 

 which come as a surprise nowadays." 



Evidence is also not wanting that floral elements further north are 

 of great antiquity. Thus Warburg (1903, pp. 482, 483) brings 

 forward reasons for the antiquity of the Flora of the Kunene — 

 Kubango Eegion (examined by Baum on his Kunene-Zambesi 

 expedition), and distinctly states that, according to his opinion, the 

 climate, with reference to the amount of rain, cannot have altered 

 to an appreciable extent for countless ages. He also points out how 

 small the affinity of that region is with the genuine so-called Cape 

 Flora of South-Western Cape Colony. There are neither BruniacecB 

 nor DiosmecB, neither Penceacece nor BestiacecB. Proteacece are repre- 

 sented only by a few species of Protea and Faurea. EricacecB were 

 not found at all by Baum. Welwitsch found in Huilla five species 

 belonging to the genera Agauria, Ficalhoa, Philiioina, and Blceria. 



We know that up to Jurassic times the interior of South Africa 

 consisted of a series of large lakes. There is no evidence that the 

 interior of Cape Colony has been under the sea or indeed under 

 water of any kind since the close of the Karroo period (Eogers, 1905, 

 p. 387). It is a fact that the period of the drying up of these lakes 



