96 



POPULAR HISTORY OF LICHENS. 



vertical is, to a certain extent, a type of the horizontal 

 range ; for, in ascending the highest mountains of tropical 

 countries, we find at their base the handsome foliaceous Li- 

 chens of warm climates, and at or below their snow-line the 

 puny crustaceous species, characteristic of Arctic regions; 

 while intermediate between these are to be met with types 

 of most of the forms common to temperate countries. As 

 bearing intimately on geographical range, we shall also here 

 regard the subject of habitat. In the coldest as well as the 

 hottest regions hitherto visited, and at the greatest eleva- 

 tions yet reached by man, Lichens have been found in greater 

 or less abundance. They attain their maximum develop- 

 ment in the form of large foliaceous Parmelias and Stictas 

 in the tropics ; but they also terminate, in the form of saxi- 

 colous Lecideas, the vegetation of the Arctic and Antarctic 

 regions. Little Table Island — at the time of Parry's fourth 

 voyage the most northern known land in the world — has its 

 rocky sides " covered with abundance of very large Tripe de 

 Roche, some Eeindeer moss, and other Lichens f while on 

 Cockburn Island Dr. Hooker, who, in his magnificent works 

 on the Cryptogamic Antarctic Mora, has made many valuable 

 contributions to our knowledge of the geographical distribu- 

 tion of Lichens, found only Lecanoras, Lecideas, and a few 



