June, 19 1 2. The Irish Naticralisi. 105 



THE RELATION OF THE PRESENT PLANT 



POPULATION OF THE BRITISH ISLES 



TO THE GLACIAL EPOCH. 



BY R. F. SCHARFF, PH.D., B.SC. 



In the December number of the Irish Naturalist Mr. 

 Clement Reid reprints the communication he made to the 

 joint sitting of the Botanical and Geological Sections of 

 the British Association meeting at Portsmouth last autumn. 

 Mr. Reid invited discussion at Portsmouth of the views 

 he brought forward, and I had the honour of being among 

 those who were asked to speak. As the time given to each 

 speaker in the discussion was limited to ten minutes, my 

 remarks were naturally very brief. Now that the readers 

 of the Irish Naturalist have been in a position to study 

 Mr. Clement Reid's views and meditate upon them, it may 

 be of interest to state more fully my reasons for dissenting 

 from them. 



At the very outset Mr. Reid imposed a curious limitation 

 on the speakers. " For this particular discussion," he 

 said, " we have a perfectly definite starting point. We have 

 merely to account for the incoming of our existing flora, 

 after an earlier assemblage had been sw^ept away almost 

 as completely and effectually as the celebrated eruption 

 wiped out the plants of Krakatoa. Any survival of our 

 flowering plants through the Glacial Epoch except in the 

 case of a few arctic and alpine species, was quite impossible." 



Thus Mr. Reid does not even deign to notice that there 

 are a few biologists who disbelieve in such a destruction 

 of the pre-Glacial flora as he depicts. He ignores their 

 existence completely. " We know," continues Mr. Reid, 

 " that during the greatest intensity of the cold all Scotland, 

 Ireland, and the greater part of England were buried under 

 ice and snow — except possibly for some higher peaks on 

 which a few arctic species survived." The expression " we 

 know " evidently implies that the last statement is a well- 

 ascertained geological fact. On the strength of this assertion 

 at any rate his audience readily believed that any survival 



