October, 1923. The Irish Naturalist. 07 



IRELAND AND SWITZERLAND : A BOTANICAL 



CONTRAST. 



By R. Lloyd Praeger, D.Sc. 



Recently I had an opportunity of studying the flora 

 of Switzerland under peculiarly favourable circumstances. 

 In the first place, I was one of a party of some 33 botanists, 

 representing seventeen different nationalities, so that we 

 had the advantage, as we went along, of comments from 

 many view-points ; and secondly, we were for over three 

 weeks conducted from end to end of the country by the 

 leading local botanists : we were taken straight from best 

 place to best place, and saw as much on one visit as most 

 people see on half a dozen. It may be of interest to attempt 

 to draw some comparisons between the vegetation of 

 Switzerland and that of our own island. 



As regards the general flora of the two areas, it may be 

 said that Switzerland possesses the great bulk of the flora 

 of which Ireland possesses only a part. Owing to its 

 central position in Europe and the great variety of con- 

 ditions, both edaphic and climatic, which prevail there, 

 Switzerland has received and retained much of the successive 

 plant-waves which have entered Europe from the greater 

 land masses which lie to the eastward. These waves beat 

 strongly across Central Europe, but diminished westward, 

 as species after species dropped out owing to competition 

 or to the intervention of barriers which arrested their pro- 

 gress : so that England has received a diminished immi- 

 gration, and Ireland a more diminished one. This general 

 east-to-west migration has been going on for a very long 

 time. The researches of Clement Reid and ]\lrs. Reid go 

 to show that during Pliocene times a flora largely exotic 

 was by degrees replaced in Europe by one closely allied to 

 that now existing, and derived no doubt mainly from the 

 Asiatic highlands. Then came the Ice Age, causing dire 

 confusion in all our records, geological, botanical and 

 zoological. In Central Europe the existing temperate 



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