88 DISTRIBUTION IN CONNECTION 



volvulus sepium should be referred to the English or 

 British Type ; and Empetrum nigrum to the Scottish or 

 Highland Type. Clematis Vitalba seems to unite the 

 English and Germanic Types ; Carum verticillatum 

 hovers between the Atlantic and Highland types ; and 

 Pinguicula lusitanica joins the Atlantic to the Hebridean 

 type. Attention to their distribution in other counties 

 will assist decision in regard to some of the doubtful 

 species. 



The local distribution of plants appears partly connected 

 with some one or more of the before mentioned condi- 

 tions, partly in connection with peculiarities of soil, and 

 partly on causes altogether unascertained. The very 

 local occurrence of Erica ciliaris and Sibthorpia europaea 

 would seem to be determined by the geographical position 

 giving a peculiarly mild and maritime climate to the 

 south-west of England. The prevalence of Ophrys api- 

 fera, muscifera, and aranifera, with other orchideous 

 plants, in the south-east of England, is doubtless mainly 

 owing to the chalk-lands being there. Northern species 

 found on mountains or moors, in bogs or rocky places, 

 for the most part show a tendency to the western side of 

 England, which might be anticipated from its more moun- 

 tainous character and humid climate. But some species 

 of the Highland type affect the north-eastern counties of 

 England exclusively, in a manner not readily explained ; 

 such are Nuphar pumila, Carex pauciflora, Cornus suecica, 

 Trientalis, and Linnaea. Except the last, these all occur 

 in the west of Scotland, and there does not appear any 

 evident cause to prevent their extension into the north- 

 west of England and Wales. Many other species, of very 

 local occurrence, equally baffle all attempts at explanation. 

 Who can even guess why Cotoneaster vulgaris and An- 

 thericum serotinum are limited to small portions of Caer- 



