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POPULAR HISTORY OF LICHENS. 



Comparatively common on rocks and boulders, especially 

 granitoid, in many parts of the Highlands, bat a somewhat 

 rare saxicolous species in lowland districts. Its spores, in 

 the specimens we have examined, are unlike those of the 

 preceding species, being fusiform, bulging in the centre, tri- 

 septate, and colourless, or somewhat intermediate in general 

 characters between those of Peltigera and Sticta. An alco- 

 holic solution of a Norwegian specimen gave a rich green 

 reaction with ammonia, a reaction which we found in no 

 other Lichen whose colorific capabilities w r e have examined. 

 This species occurs in the Antarctic regions, North America, 

 Australia, and in several other parts of the world. 



Two foreign species of this genus, Lecanora esculenta and 

 affiniSy are of great interest, from having repeatedly, under 

 extraordinary circumstances, served as the food of large 

 numbers of men and cattle, in various countries lying be- 

 tween Algeria and Tartary. They are said at various times 

 and in divers places to have appeared suddenly, covering with 

 a layer, sometimes from three to six inches thick, large tracts 

 of country ; and the inhabitants, believing their origin to 

 have been from heaven, have designated them a species of 

 manna, and have imitated their flocks, in times of scarcity 

 of food, by eating them. Some writers, speculating on their 

 nature, have gone so far as to assert their identity with the 



