160 



POPULAR HISTORY OF LICHENS. 



on the tops of hills of minor elevation, such as the Pent- 

 lands, in the vicinity of Edinburgh, or the hills surounding 

 Perth, but occurring more abundantly on the Highland 

 mountains. It frequently grows along with the preceding 

 species, with narrow or linear forms of which it may be con- 

 founded. Like most of the preceding species, it is not 

 common in fructification ; we have found it fertile however 

 on the summit of the Pentlands. Its spermogones are oval 

 or oval-truncate bodies, which constitute the blackish apices 

 of the terminal spinules or ramuscles of the laciniae. In 

 position and appearance they resemble the spermogones of 

 Cladonia rangiferina and other Cladonias. 



Cetraria cucullata (cucullus, a hood) closely resembles 

 in habit C. nivalis, with which it is usually found growing, 

 but is distinguished by its apothecia being affixed posteriorly 

 to the hood-shaped extremities of the thalline lobules. It 

 has recently been noticed as a British species, but is very 

 rare ; it is an alpine plant, growing on ground on the highest 

 mountains, or in Arctic countries, to which in Europe it is 

 chiefly confined. Like C. Islandica, we have seen specimens 

 with a beautiful purple mottling or discoloration at the base 

 of the thallus, which would seem to indicate the existence 

 in it of colorific principles. 



