Bd. IV: II) THE LICHENS. 65 



seasons. The mere collection of material is no longer all that we require. In what 

 condition are the lichens during the long winter? At what temperature does assi- 

 milation commence? It is not of real use to try experiments on plants in warmer 

 climes. Because we want to see how these small plants can live under these most ad- 

 verse conditions prevailing in the antarctic regions. Every where we find lichens on 

 the outer limits of vegetation. The power to become quite dry and yet not die is 

 their chief ecological distribution factor. We must believe that it is this property 

 which enables them to spread slowly but surely into the most inhospitable regions. 

 Unconsciously they are making their way towards the south pole but so far they 

 can have been beaten in this race only by the perpetual covering of snow. I have 

 not the slightest doubt that if bare rocks are found in the neighbourhood of the 

 South Pole that we will find Lichens growing there. 



The following table will show as has been shown before what a small difference 

 there is between the arctic and antarctic lichen floras. I have compared the lichens 

 found in Subantarctic America, South Georgia and the Antarctis with those met 

 with in the Arctic district which includes Arctic America, Greenland, Spitsbergen 

 and Iceland (Darkish. Fram): In the list I have shown the absolute numbers and 

 the percentages of those species of the three districts just mentioned which occur 

 in the Arctic district referred to: 



Frutic. 



Subantarctic America .... 30 or So % 



South Georgia 11 ■ So > 



Antarctis 10 > 52 1 



Practically half the antarctic plants then are common also to the Arctic. 



These figures also show that the similarity of subantarctic to arctic plants as far as 

 lichens are concerned is less striking than that of antarctic to arctic. Wainio has al- 

 ready made comparisons of this kind with regard to the lichens brought back from 

 the Straits of Gerlache by the "Belgica". Of the 55 species found in this region 21 

 or 38.18 % are known from arctic or temperate Europe, 9 species or 16.36 % are also 

 to be found in subantarctic America and 29 or 52.73 % were knew to Science. 

 (Wain. Belg. p. 3.) 



This point is again referred to by SCHENK (SCHENK Kerg. p. 176). But from 

 the above statistical notes the relations of arctic to antarctic lichen flora become still 

 more striking. 43 % of the antarctic lichens are found in the true arctic (and not 

 temperate regions), 53 % of the South Georgian lichens and only 24 % of the sub- 

 antarctic American species. 



9 —112865. Schwedische Südpolar- Expedition iço/ — igoj. 



