XICHEK-FLOKA Or KOETIIEEK EUROPE. 407 



I 



111 Size and number as we proceed northward and ascend the 

 Alps. In this country we are in the habit of regarding the Urn- 

 Miearicv as alpine lichens, which are to be looked for the more 

 liighly developed and more extensivety diffused the higher we 

 ascend. I have, however, in Scotland met with several species at 

 or near the sea-level — for instance, in Skye and on various Perth- 

 shire and other moors, which localities cannot be considered in 

 any sense even subalpine or montane. Similar remarks apply to 

 the variety onipJialodes of JParmelia saxatilis. Zecidea geographica 

 occurs on boulders at the sea-level around Christiansand. I have 

 niet with it at very low levels also in Scotland, but generally on 

 boulders (originally from the Highland mountains) of gneiss, mica- 

 slate or quartzite. On such boulders (erratic blocks from the 

 G-rampians) in the lowlands of Perth, within 300 to 500 feet of 

 the sea-level, I have found other lichens which are generally found 

 only in our Highlands. But a still more striking instance of the 

 counexion between lichens and the lithological character of their 

 basis of growth or support is to be found in the huge erratics of 

 the great IN'orth German plain, originally Scandinavian, which 

 support subalpine lichens totally alien to the general character of 

 the Lichen-flora of the Baltic countries. Placodmm elegans, 

 another of these cosmopolite lichens, more or less common ahjiost 

 everywhere, I found from the coast up to Sneehiitten. In some 

 of the forests of the interior clothing the hills and valleys, and 

 consisting mostly of Scotch fir and bircli, there were sometimes 



few of the higher corticolous lichens : frequently no Vsnecz or IRa- 

 'tnalince. 



The parts of Iceland and Korway which I visited were south 

 of the arctic circle ; so that geographically no part of my collec- 

 tions is entitled to the appellation arctic or sicbarctic. In a list, 

 however, which includes so many alpine species and not a few 

 cosmopolites^ we should e:spect a considerable proportion at least 

 to occur also in arctic regions. Contrasting my list vdi\\ that 

 given by my friend the Kev. "W. A. Leighton, in the Society's 

 Jom^nal, of the Lichens collected by Sir John Eichardson*, it 

 appears that about 60, le. 23-43 per cent., or nearly one-fourth 



occur 



Arctic America. This, however, is regarding arctic America as 



;imnng 



* {ex- 



Arctic America; 



ournal of the Linnean Society, (Botany) vol. ix. p. 184. 



