3o The Irish Nahi7'alist. [February, 



On page 1. we come to a real casus belli, the question as to 

 whether our most tender species have existed throughout the 

 Glacial Period in Ireland. I, for one, have always given this 

 question an unhesitating "no,'' viewing it as a matter of 

 practical experience, rather than a question to be decided by 

 geological theories. However, the argument goes merrily 

 along. It would be well to submit it to arbitration, or to take 

 a vote upon the question amongst those competent to form an 

 opinion, the minority to abide (outwardly at least) by the 

 decision of the majority. Those who have botanized in the 

 Arctic Regions, and also among the " Cantabrian Group" 

 {^Saxifraga iivibrosa, S. Gaivi, Arbichis Uncdo, Pinoidcnla 

 g7-a7idi flora, Dabcocia polifolia, Erica 77ieditcrra7ica, E. Mackaii), 

 especially practical horticulturists, will, I imagine, vote mostly 

 in the negative. It is not necessary to limit the consideration 

 of this subject to those few species (seven) of the so-called 

 Cantabrian Group (p. xlviii.), whose chief peculiarity, as 

 distinguished from several more, is the accidental one that 

 they do not now exist in the neighbouring island. It is most 

 probable they did, when they and their congeners throve in a 

 climate that suited them far better (or at least allowed them a 

 wider range) than the present climate does. Who can doubt, 

 on meeting a stra}^ dwarfed patch of Killarney Fern in 

 Donegal, or an outlying settlement of Iri.sh Spurge or Bartsia 

 viscosa in the same county, but that these were at one time 

 portions of a connected chain ? And this Cantabrian Group 

 is the still more reduced remainder of a widespread flora. No 

 matter how the arrival of these plants be explained, it seems 

 to me a sheer impossibilit}^ to suppose such organisms as these 

 could have withstood so rigorous a condition of things. The 

 Killarney Fern can, ranging as it does to Sierra I^eone, stand 

 great extremes of temperature, but its limit at the cold end of 

 the range is reached here, or in the similarly-climated west of 

 Scotland. I find more difficulty in establishing it in the open 

 than any of its western neighbours that I have experimented 

 upon. The Irish Spurge, I^arge-flowered Butterwort, and 

 Mediterranean and Connemara Heaths will make themselves 

 at home in Donegal without cultivation. Therefore I take this 

 fern as a chief stumbling block to the Pre-glacial theory. 

 A7b2ihis U7iedo\s another which has reached its limit of climatic 



