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CARL H. LINDROTH 



from Baffin Island and the North American mainland should have been much 

 easier to accomplish. Thus, the actual situation is contrary to all calculations. 

 Either of two explanations seems possible: 



1. The influence of man has been underestimated. The Palearctic element of 

 plants and animals in Greenland is largely a result of introduction by the old 

 Norsemen (and the same would apply to Iceland). 



2. A considerable part, notably the Palearctic element, of the flora and 

 fauna of Greenland (and Iceland) has immigrated during a period of geo- 

 graphical conditions fundamentally different from those of the present time. 

 This is the so-called "Land-bridge Theory". 



Fig. 3. The Palearctic and Nearctic elements of indigenous vascular plants in 



Greenland and adjacent areas. Black sectors = species without adaptation to 



long-distance dispersal. Size of circles in proportion to number of taxa (from 3 to 



55). (Data from Lindroth, 1960.) 



Commenting on point (1), it should be remembered that the Palearctic 

 plant species of Greenland have been thoroughly scrutinized by M. P. Porsild 

 (1932), considering the possibilities of introduction by man from Europe. 

 Similar calculations on the insect fauna have been made by myself for Iceland 

 (Lindroth, 1931, p. 516) and for Greenland (Lindroth, 1957, p. 268). The con- 

 clusions drawn are that both islands possess an old and indigenous Palearctic 

 element. Among other arguments, it is impossible to accept that a haphazard 

 dispersal by anthropochorous transport could result in the rather homo- 

 geneous fauna of Greenland, Iceland, and the Faeroes, that have so many 

 flightless species in common. 



We have reached our main problem here and I would like to declare my 

 position at once: The fauna and flora of the North Atlantic islands, notably of 



