FLINTS ON THE SOUTH SIDE OF THE ALPS. 125 



the problem of the birthplace of the species composing the Arctic or A]])ine floras. They 

 had been content to follow the comparatively tame process of takiniij the plants under 

 the conditions in which they were now placed, and following them in their later 

 migrations to the positions they now occupy." (Proc. H. Geogr. Soc. 1879, p. 589.) 



For convenience of reference I will quote the position at which Mr. Ball finally 

 arrived : — 



*' Of the species included in the Alpine flora, 17 per cent, are common to the Arctic 

 flora, and 25 per cent, are common to the Altai range, while the Arctic flora has 40 per 

 cent, common to the Alps and 50 per cent, common to the Altai, using this as a collective 

 name for the ranges of Northern Asia. 



" Now if, in deference to the great authorities I have named, I were to admit that 

 every one of the Arctic species common to the Alps had originally reached the mountains 

 of Central Europe by migration from the north, I ask how far that would avail towards 

 an explanation of the origin of the Alpine flora ? If we had accounted for 17 per cent, 

 of the species, what should we have to say of the remaining 83 per cent., including at 

 least four generic types peculiar to the Alps, and a very large number not found in the 

 Arctic regions — of the genera present in the higher zone of the Alps only one-half being 

 Arctic ? Is it credible that, in the short interval since the close of the glacial period, 

 hundreds of very distinct species and several genera have been developed in the Alps, 

 and — what is no less hard to conceive — that several of these non-Arctic species and 

 genera should still more recently have been distributed at wide intervals throughout a 

 discontinuous mountain-chain some 1500 miles in length, from the Pyrenees to the 

 Eastern Carpathians ? Nor would the difficulties cease there. You would have left 

 unexplained the fact that many of these non- Arctic types which arc present in the iVlps 

 are represented in the mountains of distant regions, not by the same, but by allied species, 

 which must have descended from a common ancestor : that one species of Wtilfenia, 

 for example, inhabits one small corner of the Alps, that another is found in Northern 

 Syria, while a third allied species has its home in the Himalaya " [L. c. p. 576.) 



The subject is an undoubtedly complex one. But, for my own part, I am not so 

 much impressed with the difficulties as Mr. Ball. The Alpine flora is certainly very 

 ancient, but it is scarcely possible to doubt that it is a survivor, and, as M. Alphonse 

 de Candolle points out, probably a decaying survivor, of one of which the extension was 

 at some former time far more considerable. I think that in his conclusions Mr. Ball 

 may have pressed the facts rather too hard, and that he has overlooked the enormous 

 amount of extinction which may have taken place in the Arctic flora as we now know it. 

 A mountain flora appears to me to be essentially a flora of refuge, and an island flora is 

 the fact in geographical distribution with which it best admits of comparison. 



It seemed desirable to state in this introductory note the results which, so far as could 

 be ascertained, the author was himself disposed to draw from his laljours. But it must 

 be borne in mind that the value of the Table as it is now presented to the Society is wholly 

 independent of any theoretical considerations. 



