38 



Proceedings of the Eoyal Irish Academy. 



The distribiitioiL of four cliaracteristic examples of this type is 

 giTon in. figs. 27 to 30. 



Fig. 27. — Hypericum elodes. 



Fig. 2%.— Lobelia Dortmanna. 



Fig. 29. — Pinguicula Itisiianica. 



Fig. 30. — Nitella translucens. 



It mil at once be noticed that this group, of homogeneous dis- 

 tribution, is composed of heterogeneous elements, the result of the 

 varied conditions -^vhich the marginal area provides. The leading 

 sections are alpine plants, brought in by the numerous mountain 

 groups ; calcifuge plants, rejoicing in the absence of limestone ; and 

 xerophytes, for -^hich the sands of the coast are an attraction. Xo 

 less than 23, or one half of the group, are characteristically highland 

 or upland species (though only five of these do not occasionally 



