TIIALLOPIIYTES : FUNGI 



295 



plant. In other words, a Lichen is not an individual, but a 

 firm of two individuals very unlike each other. This habit 



Fig. 270. A common liclien {Physcia) growing on bark, showing the spreading thallus 

 and the numerous dark disks (apothecia) bearing the asci.— Goldberger. 



of living together has been called symhiosis^ and the indi- 

 viduals entering into this relation are called symhionts. 



S^^^^^^^^^^^^^^^^^^^^ 



^V^: ■ ,^^::- 



Fig. 271. A common follose liclien (Parnielia) growing, upon a board, and showing 

 apothecia.— Goldberger. 

 20 



