THE WILD FLOWERS OF THE WEST OF IRELAND. 



305 



S. oypositifoUa, EupJirasia salishiirgensis, Oxyria cligijna, Sesleria 

 caerulea, Asplenium viride; wEile among the rarer concomitants 

 are Saxifraga nivalis, Epilohimn alsinefolium, Poly gala grandiflora, 

 Poa alpina, Aspidium Lonchitis, and many other interesting species. 

 These all grow on the terraced limestone cliffs and on the steep taluses 

 which subtend them, mostly at an elevation of about 1000 feet, and 

 they form a delightful study for the botanist. In this district we again 

 find evidence of that peculiar mixing of northern and southern types, 

 and of that seeming indifference to questions of elevation which we 

 have found to be so characteristic of Western Ireland. On the cliffs the 

 Maidenhair joins the various alpine species at an elevation of 700 feet, 

 and close by, at Eosses Point, the same fern grows on sea-rocks, 

 accompanied by Saxifraga aizoides, Draha iyicaria, Sesleria caerulea, 

 and Juniperus nana. 



We have seen, then, that the especial features of the West of 

 Ireland flora consist, first, in the reduction of the number of species, 

 as compared with more eastern tracts, leading to the absence of many 

 famihar wild flowers; secondly, in the presence of a small number of 

 rare species not found in the greater portion of the British Islands ; 

 and, thirdly, in the mixing together at various elevations of what we 

 have been accustomed to consider high-level and low -level plants. The 

 cause of the first of these phenomena has been already suggested. As 

 regards the third, the actual climatic and edaphic conditions which 

 plants require are so complicated, and as yet so little known, that it is 

 futile to throw out suggestions here. But as regards the second, I 

 would like to emphasize the lessons which it teaches. These Mediter- 

 ranean, Pyrenean, and North American species are, without doubt, 

 strictly native in their Irish home. No theory as to their being early 

 human introductions, though often put forward by the unlearned, will 

 for a moment pass muster with the botanist who has studied the ques- 

 tion, though it would be out of place here to detail his arguments. 

 Furthermore, the distribution of these species suggests that they belong 

 to a very old section of our flora. They have, as a whole, no peculiar 

 adaptations which would allow them to negotiate successfully a journey 

 in or over the sea; their seeds are less suited to either air- or water- 

 carriage than those of hundreds of other Spanish or Mediterranean 

 species which have not found their way to any part of our islands. 

 Again, the entire absence of the southern plants from the middle parts of 

 Ireland, England, and France tells against the theory that they came 

 from their southern homes by the route that would be now, with the 

 present distribution of land and sea, the most likely one. On the con- 

 trary, the reappearance of some of the Irish-Pyrenean plants in the 

 extreme south-west of F]ngland, and the occurrence there of several 

 plants of similar type which do not extend to Ireland, such as Erica 

 ciliaris and E. stricta, strongly support the view that we have here the 

 relics of a vegetation which was once spread along a bygone European 

 coast-line which stretched unbroken from Ireland to Spain. 



As to the American plants, the question is still more difficult, but the 



