LICHENS: THEIR USES. 19 



are the first plants to clothe the surface of bare 

 rocks ; and therefore they are the first vegetable 

 substances on newly-formed islands in the midst 

 of the ocean, thus preparing the way for higher 

 orders of plants, and finally for the abode of man. 

 Their domestic uses are of two kinds : some are 

 nourishing and medicinal in their properties, and 

 some are valuable in affording dyes. Several 

 species of lichen form the food of Canadian 

 hunters, and are called by them Tripe de RoeJie :* 

 these supplied our Arctic travellers, Franklin, 

 Kichardson, and Back, with their only means of 

 subsistence during a portion of the time spent in 

 exploring the frozen regions of the north. A 

 species called ' Iceland moss 'f furnishes a nutritive 

 jelly for invalids; another, known as 'Keindeer 

 moss 'J is the winter food of the reindeer of the 

 Laplanders. There is also a common lichen called 

 ' Lungs of the Oak/ which is used in Siberia for 

 giving a bitter to beer, and in this country as a 

 nourisliing diet for invalids. Several others are 

 said to possess medicinal qualities ; and one, called 

 by the Swedes Ulfmossa,\\ is believed by the people 



* Gyrophoras. f Cetraria islandica. I Cenomyce rangiferina, 

 Sticta pulmonacea. \\ Evernia vulpina. 



