38 ON THE BOTANICAL GEOGRAPHY OF THE 



That plants peculiar to the sea-coast, and grow- 

 ing in the sand, are also to be found in the South, 

 seems to arise from their being habituated during the 

 summer even of the northern countries to sustain a 

 considerable degree of heat, as well as from the 

 air during winter being rendered considerably 

 milder by the sea-water which remains unfrozen. 

 The Floras of northern shores are often graced 

 with flowers, which belong only to warmer climes- 

 But we must except from the rule above laid 

 down, the succulent plants of the dry part of the 

 sea-shore. Sea-weeds, as fuci, are also very ge- 

 neral ; but here we should distinguish between 

 those that grow actually on the rocks and stones 

 of the place, and such as are merely thrown on 

 the shore by the tide, and are the produce of 

 many different waters. 



Mosses are scarce in the South of Europe, be- 

 cause moist, shady, cool spots are very seldom to 

 be found in those parts. Lichens on the contrary 

 require drought and naked rocks, which they 

 here find no want of. The fungi of northern 

 and southern climes differ in some degree from 

 each other, as in the one they are the produce of 



