EXTENSION OF THE ACOTYLEDONES. 19 



in that way, a reviving vegetation, which is closely 

 connected with the decay of vegetable and animal 

 substances ; and resembling, in that way, the green 

 weeds which grow under water. The handsomer 

 mushrooms shoot from the earth, similar to other 

 plants; and are chiefly furnished with a cap, as 

 the flowers are with bells or crowns. The mush- 

 rooms are more numerous in the Temperate than in 

 the Torrid Zone : they chiefly vegetate in the latter 

 part of summer and in the autumn, but dying away 

 on the approach of frost. The line on the Picture has 

 therefore been so drawn, that their native country is 

 shewn to be much nearer to the line of snow than to 

 the Torrid Zone. 



4. The Lichens (Lichenes) are found in all parts 

 near the snow-line, being the last signs of the vege- 

 table world ; extending between the snowy plains, be- 

 yond the limit of perpetual snow to the very extreme 

 of cold. In Lapland they are found, according to 

 Wahlenberg, at a height of 500 ft. They are nume- 

 rous at the commencement of the snow-line, impress- 

 ing, even there, their character upon vegetation. 

 They, it is true, spread also to the Torrid Zone ; but 

 are at some distance from the snow-line, withdrawn 

 by a happier vegetation ; maintaining a prepon- 

 derance over all other plants only near the snow-line. 



