SOME ALPINE CLIMBERS. 217 



higher summit in Great Britain or Ireland still presents 

 examples of little isolated groups belonging to the arctic 

 or glacial flora. We know from the analogy of oceanic 

 isles that a fauna or flora entirely dependent upon such 

 waifs and strays is always fragmentary and heterogeneous 

 in the extreme : it contains only those casual members 

 of larger continental groups which are exceptionally 

 easy of transport by wind or weather. But our Scotch 

 and Welsh mountains still preserve in one place or 

 another an immense number of the old glacial plants, 

 without respect to the size of their seeds, the edibility 

 of their fruits, or the suitability of their actual embryos 

 to conveyance by birds or other known means of trans- 

 port. There is no way of explaining the frequency of 

 their occurrence except by supposing (what we have 

 otherwise every reason to believe) that they once spread 

 over the whole of the surrounding regions, and have 

 been slowly ousted from the lower districts by better 

 adapted temperate lowland forms, so that they now 

 survive only on the higher rocky points which alone 

 suit their northern constitutions. Moreover, they are 

 also for the most part moribund races ; they do not 

 belong to dominant types which are now making their 

 way triumphantly over the world, but to types left behind 

 in the struggle for existence ; and so, though they may 

 still feebly live on against intruders in their own ancestral 

 haunts, they are hardly likely to fight out the battle 

 against other species if casually dropped into the midst 

 of already occupied and settled districts. > 



A great many of these stranded glacial flowers still 

 spread widely over the larger part of the Highlands or 

 of the Welsh hills, as in the case of the little creeping 



