THALLOPHYTES : FUNGI 



79 



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

 firm of two individuals very unlike each other. This habit 



Fig. 70. A common lichen (Physcia) growing on bark, showing the spreading thallus 

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



of living together has been called symbiosis, and the indi- 

 viduals entering into this relation are called symbionts. 







^*Am2 



~!&^ J ^}^^- ^ * . 



Fie. 71. A common foliose lichen (Parmelia) growing upon a board, and showing 

 apothecia.— Goldberg kr. 



