312 Geographical Distribution of Plants 



specialisation is the loss of adaptability 1 . It is probable that many 

 elements of the southern flora are doomed: there is, for example, 

 reason to think that the singular Stapelieae of S. Africa are a dis- 

 appearing group. The tree Lobelias which linger in the mountains 

 of Central Africa, in Tropical America and in the Sandwich Islands 

 have the aspect of extreme antiquity. I may add a further striking 

 illustration from Professor Seward : " The tall, graceful fronds of 

 Matonia pectinata, forming miniature forests on the slopes of 

 Mount Ophir and other districts in the Malay Peninsula in associa- 

 tion with Dipteris conjugata and Dipteris lobbiana, represent a 

 phase of Mesozoic life which survives 



'Like a dim picture of the drowned past 2 .'" 



The Matonineae are ferns with an unusually complex vascular system 

 and were abundant " in the northern hemisphere during the earlier 

 part of the Mesozoic era." 



It was fortunate for science that Wallace took up the task which 

 his colleague had abandoned. Writing to him on the publication 

 of his Geographical Distribution of Animals Darwin said: "I feel 

 sure that you have laid a broad and safe foundation for all future 

 work on Distribution. How interesting it will be to see hereafter 

 plants treated in strict relation to your views 3 ." This hope was 

 fulfilled in Island Life. I may quote a passage from it which 

 admirably summarises the contrast between the northern and the 

 southern floras. 



"Instead of the enormous northern area, in which highly organised 

 and dominant groups of plants have been developed gifted with 

 great colonising and aggressive powers, we have in the south three 

 comparatively small and detached areas, in which rich floras have 

 been developed with special adaptations to soil, climate, and organic 

 environment, but comparatively impotent and inferior beyond their 

 own domain 4 ." 



It will be noticed that in the summary I have attempted to give 

 of the history of the subject, efforts have been concentrated on bring- 

 ing into relation the temperate floras of the northern and southern 

 hemispheres, but no account has been taken of the rich tropical 

 vegetation which belts the world and little to account for the original 

 starting-point of existing vegetation generally. It must be re- 

 membered on the one hand that our detailed knowledge of the 

 floras of the tropics is still very incomplete and far inferior to that 



1 See Lyell, The Geological Evidences of the Antiquity of Man, London, 1803, p. 446. 



2 Report of the 73rd Meeting of the British Assoc. (Southport, 1903), London, 1904, 

 p. 844. 



3 More Letters, n. p. 12. Wallace, Island Life, pp. 527, 528. 



