2io SPENCER MOORE [September 



" Scandinavian " flora ? A considerable portion of it must have been 

 in existence then, and it is difficult to conceive how the ancestors of so 

 large and important an element in the earth's vegetation could have 

 found sufficient room in the few extreme northern lands then suitable 

 to them. But during Eocene and Miocene times a large part of 

 the antarctic continent must have had a climate suitable to the 

 support of " Scandinavian " forms ; and if we can suppose, and there 

 seems little difficulty in the supposition, warranted as it is by facts of 

 distribution, that the antarctic continent was then continuous with 

 South America, and had outlying lands permitting of interchange with 

 South Africa and Australia, a portion, and no inconsiderable portion, of 

 the flora now considered to be of northern origin may well have taken its 

 rise in these southern lands. It was probably during the Pliocene 

 period that the Scandinavian flora first became important in Northern 

 Europe. Pliocene times must have been highly favourable to the 

 diffusion of herbs which flourish best in colder temperate climates, for 

 not only did cold conditions then prevail, but there were ready for 

 colonisation large areas raised during the mountain-making Eocene and 

 Miocene periods. It is conceivable, therefore, that much interchange 

 between northern and southern lands may have taken place during 

 this period. 



But it may perhaps be that the Pliocene age is too recent for such 

 a relation as has been sketched to have existed between the antarctic 

 continent and lands lying to the north of it, though the recent 

 discovery in South America of a carnivorous Marsupial allied to 

 Thylacinus suggests that such a relation existed during later tertiary 

 times. Yet the point to be remembered is that large areas in the 

 south have enjoyed a climate eminently suitable to the evolution of 

 forms best fitted to flourish in the colder temperate zones, and, 

 moreover, that during long periods the larger extent of such areas has 

 been in the south. The problem, too, how southern forms could have 

 reached the north is no greater than the problem how northern forms 

 could have penetrated into antarctic lands. All we know is that a 

 genus could have had its origin in but one area, and that, as regards 

 temperate forms, there is much generic resemblance between the 

 northern flora and the southern ; but there is no justification for the 

 view that all the genera common to both had their origin in the north 

 and none of them in the south. 



It is also necessary to receive with grave doubt any conclusion 

 relative to the inherent superiority of certain floras as a whole over 

 others, and this although several species of supposed northern origin 

 are capable of ready acclimatisation in foreign lands, and can some- 

 times flourish at the expense of endemic forms; for in every flora there 

 are species more widely diffused and with greater powers of adaptation 

 than others. Has anybody ever argued, from the rapid spread of 

 Anacharis alsinastrum in our streams a few years back, from the way 



