12 The Irish XafitraJisf. December, 



itself had its origin in an oceanic climate combined with 

 an increased precipitation. ' A large part of central 

 Europe was covered by the sea in Tertiarv times so that 

 the climate must then have been more oceanic and more 

 equable than it is now. We know in fact from the remains 

 of both plants and animals that the seas had a fauna allied 

 to that of the Mediterranean and that the flora of the land 

 was semi-tropical, at an\' rate in Yhe earlier parts of the 

 Tertiary Era. As extremely few of the alpine plants 

 possess hard leathery leaves which might favour the survival 

 of their imprints in mud or beds of cla}', we know nothing 

 of the past range of the great mass of these plants. 



No doubt pre-(ilacial deposits containing seeds are 

 known, but so far only from the east coast of England, 

 and the}^ contain no seeds of alpine plants." There is no 

 positive evidence therefore that the majority of the alpine 

 plants have originated and s[)read in Tertiary times, 

 although this opinion i^ put forward by some very eminent 

 botanists, among them Prof. Engler."' 



If this view should prove to be correct, the oceanic 

 low-level habitat of some arctic-alpine plants such as 

 Drvas octopetala should not be considered as abnormal. 

 On the contrary we should have to conclude that their 

 habitat in the remote past, long before they were scattered 

 from their original stations, was in the lowlands. Their 

 Irish habitat would thus be a true relict of the past — a 

 survival from Tertiary times. Their mountain habitat 

 would have to be looked upon as an abnormal one to 

 which the alpines had only gradually adapted themselves, 

 having met there conditions suitable to their requirements. 



Bray. 



1 Brockmann-Jerosch, H. : — Die \>getation des Diluviums in dcr 

 Schweiz. Verhandl. d. Schweiz. Xaturf. Gesellsch. 1920. 



2 Reid, C. and E. M. Reid : — The pre-glacial flora of l^ritain. Journ. 

 Linn. See. London (Botany), vol. xxxviii., 1907. 



^ Engler, a. :— Monographic der Gattung Saxifraga. Brc.slau, 1872. 



