30 SCIENTIFIC WOKK, 1860-1865 



in Iceland ; then again the absence of Cdltha anywhere in 

 Greenland, and other plants that swarm elsewhere all round 

 the circle, is as fatal as any indirect evidence can be to the 

 population of the whole by chance migration. If you 

 intend to ask me when we meet how I account for richness 

 of Lapland Flora, I will take care to flee your presence. 

 I am utterly at sea when I attempt to jog out of the quiet 

 locus standens of Lapland being the focus for lattermost 

 migration. I grant that the idea may be utterly false, of 

 its being the centre. I have some vague notion that the 

 pre-glacial focus of Scandinavian plants was a terra polaris 

 that United Greenland, Iceland and Scandinavia (not perhaps 

 in latitude, but somehow) ; what it may have embraced to 

 the North of America and Asia I neither know nor care ; 

 for it is quite clear that there have been very great modern 

 changes of level amongst the Polar American Islands, which 

 I suppose are rising. I only call this vegetation Scandinavian 

 because it is now represented best in Scandinavia, and this 

 partly because of present climate of Scandinavia and partly 

 because of its mountains having afforded a favoring climate 

 to said plants during post-glacial warm period. I cannot 

 too strongly impress the fact that Greenland is unaccount- 

 ably poor in plants ; its comparatively equable (for an arctic) 

 climate is singularly favorable for a northern Flora. In 

 summer the line of perpetual snow in Disko is about 4000 

 feet I am told. Just look again at the list of Arctic 

 species at p. 272 found in Europe and America but not in 

 Greenland. I have not a shadow of doubt about wholesale 

 extinction in East N. America. 



The criticism of naturalists able to appreciate the value 

 of the botanical argument was the only criticism he considered 

 worth having. Thus on August 20 he could tell Darwin, ' I am 

 hugely pleased with Asa Gray's review of my Arctic Essay.' 1 



On the other hand, a review by Dr. Dawson, 2 a geologist 

 with inadequate knowledge of botany, attacked the Essay 

 specially on geological grounds, and accused Hooker of 



1 American Journal of Science and Arts, xxxiv., and in Gray's Scientific 

 Papers, i. 122. 



1 Sir J. William Dawson, C.M.G., F.R.S. (1820-99), was born in Nova 

 Scotia, and studied in Edinburgh 1841-2. He was President of the McGill 

 University, Montreal, from 1855-93. 



