LETTER XXV. 



THE LICHEN TRIBE — THE MUSHROOM TRIBE- 

 THE SEAWEED TRIBE. 



Plate XXV. 



At last we have nearly reached the limits of the 

 vegetable world, and find ourselves upon the confines 

 of that mysterious region where animal and vegetable 

 natures become so blended, that the philosopher is 

 obliged to admit the weakness of his systematical dis- 

 tinctions, and to abandon the attempt at drawing a 

 line between vitality and volition. In explaining to 

 you the structure of the three lowest tribes in the 

 vegetable kingdom, I do not propose to fatigue your 

 attention by the minute, and specific details in which 

 they so peculiarly abound ; but I shall content myself 

 with sketching out the great features by which they 

 are usually distinguished. 



When we quit Mosses and Jungermannias, with 

 the other plants of a similar nature, we find ourselves 

 amonof beings in which all traces of stems and leaves 

 have disappeared, and which consist of nothing but 

 thin horizontal expansions of vegetable matter in 

 which a few harder, and differently formed kernels 

 or shields are imbedded. In some of these the colour 



