318 Geographical Distribution of Plants 



must continually be happening 1 ." If we give to "continually" a 

 cosmic measure, can the fact be doubted? All this, in the light of our 

 present knowledge, is too obvious to us to admit of discussion. But 

 it seems to me nothing less than pathetic to see how in the teeth 

 of the obsession as to continental extension, Darwin fought single- 

 handed for what we now know to be the truth. 



Guppy's heart failed him when he had to deal with the isolated 

 case of Agathis which alone seemed inexplicable by known means of 

 transport. But when we remember that it is a relic of the pre- 

 Angiospermous flora, and is of Araucarian ancestry, it cannot be 

 said that the impossibility, in so prolonged a history, of the bodily 

 transference of cone-bearing branches or even of trees, compels us 

 as a last resort to fall back on continental extension to account for 

 its existing distribution. 



When Darwin was in the Galapagos Archipelago, he tells us that 

 he fancied himself " brought near to the very act of creation." He 

 saw how new species might arise from a common stock. Krakatau 

 shows us an earlier stage and how by simple agencies, continually at 

 work, that stock might be supplied. It also shows us how the mixed 

 and casual elements of a new colony enter into competition for the 

 ground and become mutually adjusted. The study of Plant Distri- 

 bution from a Darwinian standpoint has opened up a new field of 

 research in Ecology. The means of transport supply the materials 

 for a flora, but their ultimate fate depends on their equipment for 

 the "struggle for existence." The whole subject can no longer be 

 regarded as a mere statistical inquiry which has seemed doubtless 

 to many of somewhat arid interest. The fate of every element of 

 the earth's vegetation has sooner or later depended on its ability to 

 travel and to hold its own under new conditions. And the means by 

 which it has secured success is in each case a biological problem 

 which demands and will reward the most attentive study. This is 

 the lesson which Darwin has bequeathed to us. It is summed up in 

 the concluding paragraph of the Origin'* : " It is interesting to 

 contemplate a tangled bank, clothed with many plants of many 

 kinds, with birds singing on the bushes, with various insects flitting 

 about, and with worms crawling through the damp earth, and to 

 reflect that these elaborately constructed forms, so different from 

 each other, and dependent upon each other in so complex a manner, 

 have all been produced by laws acting around us." 



1 Life and Letters, n. pp. 56, 57. 2 Origin of S})ecies (6th edit.), p 429. 



