INTRODUCTION 13 



mountains far away from their kin in the lowlands of the arctic 

 and sub-arctic regions. 



The presence of boreal species in high mountains in lower 

 latitudes, is a familiar feature of plant distribution in Europe and 

 the United States. A number of species for example, occur at the 

 summit of the White Mountains which are found at sea-level in 

 Labrador and Greenland, and the alpine summits of the Rocky 

 Mountains and Sierra Nevada have species which inhabit the 

 lowlands of Alaska and arctic British America. 



In the northern hemisphere, therefore, it was the extensive 

 Pleistocene glaciation which must be considered the greatest 

 single factor in the establishment of the temperate floras of the 

 present day. 



Our knowledge of the conditions in the southern hemisphere 

 during the Tertiary is very incomplete, and the origin of the 

 modern south temperate floras is very uncertain. 



Unlike the arctic regions, the antarctic continent is separated 

 from the temperate zone by a broad ocean belt, so that the south 

 temperate lands are completely isolated, and the relationships 

 of the floras of South Africa, South America and Australasia, are 

 much less intimate than those of Eurasia and temperate North 

 America. 



Nevertheless there is sufficient resemblance, especially between 

 sub-antarctic South America and Australasia, to warrant the 

 assumption of some former land connection, probably via some 

 northern extension of the present antarctic continent. 



The latter, at present, is practically destitute of vegetation, 

 but there is sufficient fossil evidence, to show that within a few 

 degrees of the pole there formerly flourished plants which must 

 have needed a temperate climate, at least, for their existence, and 

 fossils of a later date from Seymour Island, south of Patagonia, 

 show remains of species closely related to some of those now found 

 in New Zealand. 



Our knowledge of these antarctic fossils is too meagre to permit 

 any positive conclusions as to the character of the ancient antarctic 

 flora as a whole, or to decide whether there was a continuous 

 circumpolar Tertiary flora as in the northern hemisphere. Should 

 such be the case, it would explain the occurrence of the same 

 antarctic types in Patagonia and Australasia, which might be 



