96 DISTRIBUTION OF BRITISH PLANTS 



Faroe without any native tree, and supporting only shrubs 

 of insignificant dimensions. In Mr. Trevelyan's list, 

 14 shrubby species occur, two only being excluded 

 from the British flora, namely, Salix arctica and Ledum 

 palustre. All of them occur in Iceland or Greenland, 

 excepting Salix phylicifolia (?), S. hastata, and Erica 

 cinerea. Mr. Trevelyan has given some notices respect- 

 ing the elevations at which several species were observed 

 to grow ; thus, Salix hastata was seen at the sea level, 

 and Salix herbacea usually above 1000 ft, though one 

 specimen was noticed so low as 50 ft. Ascending the 

 N. E. side of Mallingsfiall, in the island of Videroe, the 

 first plant of Salix herbacea occurred at 1088 ft, and of 

 Azalea procumbens at 1382 ft. These, with Empetrum 

 nigrum and Vaccinium Myrtillus, attained the summit, 

 which is 2366 feet. 



The British Islands make the next step, and form the 

 connecting link between the coasts and isles before men- 

 tioned and the European continent. Of course the N.W. 

 line of all the remaining indigenous trees and shrubs 

 crosses Britain. All occur at or near the sea level, except 

 the following, and several willows not specified here : — 



Salix reticulata, I have not seen below 700 yds. 



Azalea procumbens, at 500 yds (?) in Orkney ; 500 yds in Suther- 

 land ; 600 or 650 yds in the W. of Invernesshire ; at 

 700 yds on the Grampians. 



Salix herbacea, at 500 yds (?) in Orkney ; 600 or 650 yds in the 

 W. of Invernesshire ; 750 yds in the N. of England. 



Betula nana, at 500 to 550 yds in Aberdeenshire. Whether at a 

 lower elevation elsewhere I cannot say. Probably so in 

 Lanarkshire. 



Vaccinium uliginosum, at moderate elevations ; but I have never seen 

 it actually on the sea level. At 500 feet in the N. of Eng- 

 land, according to Winch. 



Arbutus alpina, probably down to the sea level in the N.W. of 



