B8 GUIDE TO THE STUDY OF LICHEKS. 



are formed of the elements of both symbionts and can 

 therefore develop into a new lichen. Their structure 

 and function will be more fully described elsewhere. 

 Lichens are also more long lived than fungi. The 

 majority of fungi terminate existence with the matura- 

 tion of the spores, while most lichens have an indefin- 

 itely prolonged existence. Some of the Cladonicis, for 

 example, may live hundreds of years ; the apical portion 

 continues to grow, while the basal portion dies away. 



Sufficient reasons have been given to show that 

 lichens are neither fungi nor algae ; they must there- 

 fore be treated as a distinct class of plants. Other 

 characters peculiar to lichens will be mentioned later. 



