LICHENS. 131 
especially in the west of Scotland, in the greatest 
abundance. The latter lichen is equally common, 
growing among Sea-pink and yellow Parmelias on 
rocks along the sea-shore, to which it gives a 
shaggy appearance by its long rigid greenish 
white tufts. On the Standing Stones of Stennis in 
Orkney it grows to a length of six or eight inches ; 
while the ancient sea-cliffs at Appin, near Oban, 
are fringed with immense masses of it nearly a 
foot in length, presenting, along with the varied 
and richly coloured flowering vegetation which 
adorns the ledges and crevices, a most picturesque 
sight. This Ramalina is found in all parts of the 
world, on the shores of New Zealand and the 
Antarctic Islands, as well as in the most northern: 
regions, and is one of the most widely distributed 
lichens in the world. In temperate countries it 
occupies the same place on the sea-shore which 
the Orchil (Roccella tinctoria) does in tropical and 
southern zones. Another gea-coast lichen is the 
Placodium canescens, found abundantly on trees in 
England near the sea, and on walls and rocks in 
Scotland. It whitens the walls of ‘Craigmillar 
Castle, and the rocks of Arthur’s Seat and 
Salisbury Crags, near Edinburgh, and gives an 
appearance of being white-washed to the loose 
stone dike that runs up from the shore to 
Dunstaffnage Castle, near Oban. It is one of the 
