GEOGRAPHICAL DISTRIBUTION. 97 



Mosses, constituting the last remnants of vegetation in the 

 Southern Hemisphere. Some Lichens may be considered cos- 

 mopolites, such as our common Leeanora sttbfusca, Cladonia 

 pyxidata, and Usnea barbata. From the evidence of travellers 

 it would appear that there is a great similarity of species in 

 different parts of the world. Robert Brown has shown that 

 of New Holland Lichens two-thirds are natives also of 

 Europe ; Don has pronounced the majority of Himalayan 

 Lichens to be identical with European species ; and the 

 same thing has been noticed in regard to those of South 

 America by Humboldt, and of North America, the Arctic 

 and Antarctic regions, by various authors. Many of our 

 commonest British Lecanoras, Lecideas, Cetrarias, Cladonias, 

 Parmelias, Peltigeras, Ramalinas, Sphserophorons, and Ste- 

 reocaulons are to be found, according to Dr. Hooker, in the 

 Falkland Islands, Graham's Land, Kerguelen's Land, and 

 other islands or continents of the Antarctic regions ; accord- 

 ing to "Royle, on the Himalayas ; to Nylander, in Chili • to 

 Martius, in equatorial Brazil and South America; to Parry 

 and other Arctic voyagers, in Spitzbergen, Lapland, Iceland, 

 Nova Zembla, and more northern polar islands or continents. 

 In proportion as our knowledge of Lichenology becomes 

 improved, and especially in proportion as we become ac- 



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