ATLANTIC SPECIES OF HEPATICK IN SCOTLAND 121 



distance over the western watershed in the Trossachs, and 

 this is the most eastern point in the centre of Scotland 

 where the hepatic flora is rather western than eastern. 

 Owing to the configuration of Scotland, especially with its 

 south coast being practically on the Atlantic, longitudinal 

 lines for the whole of the country cannot be satisfactorily 

 quoted. 



Those species of Atlantic hepatics which are confined 

 to the mountains have in several cases a more extended 

 distribution eastward. This is so principally with those 

 which occur on moist rock ledges, some of which are found 

 in the Aberdeenshire Grampians. The wet climate of the 

 mountains approximates more to that of the west coast, 

 and these species are able to withstand a considerable 

 amount of cold. On the other hand our only alpine 

 Atlantic species confined to dry rocks, Gymnouiitrium crenu- 

 latuvi, while it is a common plant on the west coast, 

 becomes gradually rarer as it extends to the east, until it 

 becomes exceedingly rare on the Aberdeen Grampians. 

 There does not appear to be much sheltered ground on our 

 north coast, but it has not yet been well searched except 

 in the Caithness portion. None of the characteristic species 

 of the west coast have been found there, but one Atlantic 

 species, Pleurozia purpurea, which affects wet exposed moors, 

 is found in quantity in the northern part of the main- 

 land. 



Our Atlantic species may be divided as follows, as 

 far as our knowledge of their distribution allows in the 

 meantime. 



i. Species known only on the western watershed : 



Sphenolobus Pearsoni. Colurolejeunea calyptrifolia. 



Acrobolbus Wilsoni. Cololejeunea minutissima. 



Plagiochila tridenticulata. Lejeunea Macvicari. 



Adelanthus decipiens. Drepanolejeunea hamati- 



folia. 



Lepidozia pinnata. Harpalejeunea ovata. 



Radula voluta. Marchesinia Mackaii. 



R. aquilegia. Jubula Hutchinsiae. 



R. Carringtonii. Frullania microphylla. 



